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Inner coating of long-narrow tube by plasma sputtering
Surface and Coatings Technology 131 Ž2000. 278᎐283
Inner coating of long-narrow tube by plasma sputtering Hiroshi FujiyamaU Faculty of Engineering, Nagasaki Uni¨ ersity, 1-14 Bunkyo, Nagasaki 852-8521, Japan
Abstract Long-narrow tubes are widely used in industry as water pipes, gas pipes and cooling pipes, etc. It is necessary to protect the inside of a metallic or dielectric tube against inner wall corrosion due to the inner surface being damaged by high temperature fluid or chemically reactive liquid. For thin film sputter coating on the inner wall of long-narrow tubes, the authors have developed the coating reactors using a coaxial magnetron pulsed plasma ŽCMPP. and a coaxial electron cyclotron resonance plasma ŽCECRP.. 䊚 2000 Elsevier Science B.V. All rights reserved. Keywords: Sputter coating; Inside coating of tube; ECR plasma; Magnetron plasma
1. Introduction
2. Coaxial magnetron pulsed plasma (CMPP)
Narrow tubes are widely used in industries as water pipes, gas pipes, cooling pipes for nuclear reactors, and so on. These tubes are often required to have better performances in corrosion and wear behaviors. It is necessary, therefore, to protect the inside of tubes. For the purpose, several investigations on inner coatings have been reported w1᎐7x. In our laboratory, plasma reactors have been developed by using magnetron hollow cathode discharges w8x, coaxial magnetron pulsed discharges ŽCMPP. w9᎐11x and coaxial electron cyclotron resonance discharges ŽCECRP. has been developed as reported in the previous article w12᎐15x. In the present paper, we report on the experimental results regarding discharge characteristics, plasma generations and thin film depositions on inner wall of narrow tubes using the CMPP and CECRP reactors.
2.1. Experimental
U
Tel.: q81-95-847-6437; fax: q81-95-847-6437. E-mail address: [email protected] ŽH. Fujiyama..
The CMPP device shown in Fig. 1 consists of a long cylindrical vacuum chamber, 50 mm in diameter and 1700 mm in length, a turbo molecular and rotary pumps for less than 10y6 torr in base pressure, water-cooled solenoid coils arranged coaxial around the chamber and pulse power supply. Glass tubes of 8 mm in inner diameter, 1 mm in thickness and 600 mm in length were set parallel to a cathode rod. Pulsed discharges were generated between a long cathode rod of 2 mm in diameter and 800 mm in length and a grounded short anode ring of 6 mm in the inner diameter and 5 mm in length. A strong uniform magnetic field was applied parallel to the cathode to increase the discharge current and decrease the operating gas pressure which were effective for high deposition rate and adhesion of the coated films. The target atoms were sputtered off and deposited onto the inner surface of glass tube. Typical experimental conditions were as follows: argon pressure Ps 30 mtorr, magnetic
0257-8972r00r$ - see front matter 䊚 2000 Elsevier Science B.V. All rights reserved. PII: S 0 2 5 7 - 8 9 7 2 Ž 0 0 . 0 0 8 0 1 - X
H. Fujiyama r Surface and Coatings Technology 131 (2000) 278᎐283
279
Fig. 1. Experimental setup of CMPP.
flux density B s 1050 G, negative pulse voltage VP s 1.5᎐2.5 kV, pulse repetitive frequency 1 kHz and pulse width s 10 s, i.e. the duty cycle of 1%. The axial distribution of film thickness was measured by a light absorption method. Relative film thickness can be estimated by FT s log e Ž I0rI x ., where I0 is the light ŽLED: GaAsP:N, center wavelength 630 nm, halfwidth 45 nm. intensity passed through a non-deposited area of a glass tube and I x is at measuring position of film thickness. 2.2. Results and discussions 2.2.1. Extended anode effect In order to coat films onto an inner surface of a long tube by sputtering, plasmas must be shifted along the tube. In the CMPP device, pulsed plasmas are shifted away from the anode automatically with deposition time. The reason is that the conductive films deposited near the native anode located at the tube end play a role of an anode, as a consequence, plasmas are generated to the inner part of the tube Žsee Fig. 2.. Thus, this phenomenon was named as extended anode effect. Axial distributions of titanium ŽTi., tungsten ŽW. and gold ŽAu. film thickness coated by the CMPP method were investigated as a parameter of deposition time for Ps 30 mtorr, B s 1050 G, VP s y2.5 kV, f s 1 kHz and s 10 s, respectively. Fig. 3 shows the results for Ti coating. In these experiments, the anode was located at X s 0 cm. It was clear that all distributions were wide with the deposition time because of the extended anode effect. Note that measured film thickness cannot be compared with the other film’s one because of the difference in the deposition time and the light absorption of films. Deposition times were changed in each
film material ŽTi: 60᎐120 s, W: 10᎐20 s, Au: 5᎐8 s. for convenience of the measurement of film thickness in the light absorption method. Here, in the case of Ti film, the deposition rate estimated from absolute film thickness was 95 nmrmin Ž0.16 nmrpulse. at 5 cm from the anode. 2.2.2. Shifting ¨ elocity The shifting plasmas were observed by optical emission spectroscopy w10x. Fig. 4 shows that the shifting velocities in the case of depositions of Ti, W and Au films for 30 mtorr, B s 1050 G, VP s y2.5 kV, f s 1 kHz and s 10 s. Sputtering yields of these materials Žatomsrion. are Ti: 0.51, W: 0.57, Au: 2.40 ŽArq, 500 eV. and resistivities Ž ⍀ m. are Ti: 47.0= 10y8 , W: 5.50= 10y8 , Au: 2.35= 10y8 Žat 293 K.. It was found
Fig. 2. Principle of the extended anode effect.
280
H. Fujiyama r Surface and Coatings Technology 131 (2000) 278᎐283
Fig. 4. Shifting velocities for various metallic films. Fig. 3. Axial distributions of Ti film thickness as a parameter of sputter᎐deposition time.
that the shifting velocity increased as sputtering yield was high and resistivity was low. Certain film thickness seems to be necessary for the appearance of the extended anode effect, so it is natural that the shifting velocity increases in the case of film materials which have high sputtering yield. Although Ti and W have nearly same sputtering yield, these shifting velocities were quite different. It may be caused by the difference of the resistivity. The shifting velocities which are normalized by sputtering yields increased with the decrease in resistivity of film material, because the film thickness required for the appearance of the extended anode effect becomes thinner as film resistivitly is lower. In short, the shifting velocity depends on the time up to which the deposited film can be anode.
3. Coaxial ECR plasma (CECRP) 3.1. Experimental The experimental setup is shown in Fig. 5. Plasmas were generated inside the tube by ECR which was possible to discharge at low pressures of less than 10y3 torr and narrow gap of several millimeters. Operational gases were pure Ar and N2rAr mixture for TiN reactive coatings. The base pressure of the vacuum chamber was less than 5 = 10y6 torr. Sputter target was a titanium rod Ž5 mm in diameter and 500 mm in length., and the substrate was a grounded stainless steel tube Ž30 mm in inner diameter and 480 mm in length. or an insulated glass tube Ž27 mm in inner diameter and 480 mm in length. which was inserted in a metallic tube. Microwave power was supplied by a magnetron at a frequency of 2.45 GHz and maximum continuous power
Fig. 5. Experimental setup of CECRP.
H. Fujiyama r Surface and Coatings Technology 131 (2000) 278᎐283
281
Fig. 6. Applied magnetic field pattern and their axial profiles by using mirror-type magnetic field.
of 200 W, and was transmitted in TEM mode which had no cutoff frequency. The coaxial cable and a coaxial tube as a target and the substrate were connected by a tapered tube to transform a diameter of outer conductor from 8 to 30 mm. Five solenoid coils were set around the process chamber at equal spaces apart. Magnetic field excited by the coils was controlled by using a computer and a switching regulator. It allows to scan the ECR points and transport plasma along the tube axis. For sputter coating, DC bias voltage was applied to the target. Mirror-type magnetic field was formed by switching on two coils. By using such a mirror-type magnetic field, we have succeeded in low-pressure discharge, high deposition rate and good uniformity of axial distribution of deposition rate in metallic tubes w15x. Mirror-type magnetic field can confine initial electrons within the ECR region. Fig. 6 shows the current switching pattern of two coils when the inner surface of tube should be coated all over. As the magnetic field for two coils can always be applied, it is possible to widely apply a magnetic field with several ECR points in the axial direction of the tube. Therefore, electron loss to the inner wall and axial direction of the tube can be decreased, and microwave power can be absorbed efficiently to the plasma.
for low pressure and low microwave incident power could be realized in the insulated glass tube. 3.2.2. Axial distribution of sputter deposition of insulated glass tube As the plasma position could be transported by using this control system of magnetic field, we performed Ti inner coating of the insulated glass tube. Current switching pattern of two coils was used by Coil Ž1.2. ᎐ Ž2.3. ᎐ Ž3.4. ᎐ Ž4.5. Žsee Fig. 6. and the deposition time was 5 min for each switching pattern. Here, Ar pressure P was 0.1 mtorr, the microwave incident power Pinc was 100 W, the target voltage Vt was y400 V, and the maximum magnetic flux density Bmax was 1020 G. The optical absorption method was used for the measurement of deposition rate. Fig. 8 shows the axial distribution of deposition rate in the insulated glass tube for each switching pattern. In each switching pattern, it was a little different in deposition rate. Especially, the deposition rate near the tube end apart from the microwave window was low. However, by
3.2. Results and discussions 3.2.1. Discharge characteristics Fig. 7 shows the discharge characteristics in insulated glass tube compared to that in metallic tubes. The plot shows the minimum microwave incident power for breakdown as a function of Ar pressure by using the mirror-type magnetic field for Coil 3 and 4. The electric field of microwave in discharge space increases by inserting the insulated glass tube in a metallic tube. Moreover, initial electrons for breakdown should be confined by negatively charged insulated glass surface. Although the discharge gap length of insulated glass tube is shorter than that of the metallic tube, discharge
Fig. 7. Discharge characteristics in the insulated glass tube compared to that in the metallic tube.
282
H. Fujiyama r Surface and Coatings Technology 131 (2000) 278᎐283
pressure Ptotal of 0.14 mtorr. The atomic composition ratio, NrTi, of the films was unity and almost homogeneous in the films. Although the oxygen contamination was so high, the deposited film showed a gold color.
4. Conclusions In order to coat thin films onto the inner surface of narrow tubes with high aspect ratios in length to inner diameter, we have developed a CMPP device. Using the extended anode effect, we have succeeded in coating a Ti thin film onto the inner surface of a narrow glass tube of 1000 mm in length and 8 mm in inner diameter in a double ended anode coaxial magnetron pulsed plasmas ŽDCMPP. device. In coaxial ECR plasmas, it was found that the electric field of microwave in insulated tube was increased, and the discharge for low pressure and low microwave incident power was realized by inserting insulated tubes into metallic tubes. The titanium films have been successfully coated on the inner wall of the glass tube of 27 mm in inner diameter and 480 mm in length by scanning the mirror-type ECR magnetic field. The present inner coating system was applied to reactive sputter deposition of TiN films, and the trial deposition was successfully performed by TiN inner coating of metallic tubes of 30 mm in inner diameter and 480 mm in length. Fig. 8. Axial distribution of deposition rate for each switching pattern in the insulated glass tube.
controlling the deposition time in each switching pattern, for example, the deposition time in Coil Ž4.5. is much longer, the coating uniformity might be able to verify.
3.2.3. Titanium nitride inner coating of metallic tube by reacti¨ e sputtering Titanium nitride ŽTiN. coatings have been used very successfully in a variety of applications because of their excellent properties, such as hard and anti-wear and good corrosion resistance w16x. So the present inner coating system was applied to a reactive sputter deposition of TiN films. The glass substrate Ž5 = 5 mm. was set in the metallic tube at the position z s 250 mm from the substrate edge Ž zs 0.. Plasma was generated inside the metallic tube by using mirror-type magnetic field for Coil 3 and 4, and the TiN films were deposited for 30 min for Ar flow rate of 0.1 sccm, N2 flow rate of 0.1 sccm and total
Acknowledgements The author would like to thank Dr H. Kuwahara, Dr K. Kuwahara, M. Morita, S. Sugimoto and T. Nagano for their technical help with the researches. This work was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture ŽKiban-BŽ2., 10558066.. References w1x Y. Matsuzawa, H. Yasuda, J. Appl. Polym. Sci., Appl. Polym. Symp. 38 Ž1984. 65. w2x T. Ihara, H.K. Yasuda, J. Appl. Polym. Sci., Appl. Polym. Symp. 46 Ž1990. 511. w3x J.A. Sheward, Surf. Coat. Technol. 54r55 Ž1992. 297. w4x R. Hytry, W. Moller, R. Wilhelm, A.V. Keudell, Vac. Sci. Technol. A11 Ž1993. 2508. w5x R. Hytry, W. Moller, R. Wilhelm, Surf. Coat. Technol. 74r75 Ž1995. 43. w6x W. Ensinger, Rev. Sci. Instrum. 67 Ž1996. 318. w7x W. Ensinger, Surf. Coat. Technol. 86r87 Ž1996. 438. w8x H. Kawasaki et al., Mater. Sci. Eng. A140 Ž1991. 682. w9x H. Fujiyama et al., Surf. Coat. Technol. 98 Ž1998. 1467.
H. Fujiyama r Surface and Coatings Technology 131 (2000) 278᎐283 w10x Y. Uchikawa et al., Thin Solid Films 112 Ž1999. 185. w11x S. Sugimoto et al., Jpn. J. Appl. Phys. 38 Ž1999. 4342. w12x T. Shigemizu, N. Ohno, H. Fujiyama, Mater. Sci. Eng. A139 Ž1991. 312. w13x H. Fujiyama, H. Kawasaki, T. Fujiyama, S. Takagi, Surf. Coat.
283
Technol. 59 Ž1993. 140. w14x E. Morisaki, H. Fujiyama, Surf. Coat. Technol. 98 Ž1997. 834. w15x E. Morisaki, T. Nagano, H. Fujiyama, Trans. IEE Jpn. Žin Japanese. 177-A Ž1997. 1207. w16x Y. Miyamoto et al., Thin Solid Films 270 Ž1995. 253.
Inner coating of long-narrow tube by plasma sputtering Hiroshi FujiyamaU Faculty of Engineering, Nagasaki Uni¨ ersity, 1-14 Bunkyo, Nagasaki 852-8521, Japan
Abstract Long-narrow tubes are widely used in industry as water pipes, gas pipes and cooling pipes, etc. It is necessary to protect the inside of a metallic or dielectric tube against inner wall corrosion due to the inner surface being damaged by high temperature fluid or chemically reactive liquid. For thin film sputter coating on the inner wall of long-narrow tubes, the authors have developed the coating reactors using a coaxial magnetron pulsed plasma ŽCMPP. and a coaxial electron cyclotron resonance plasma ŽCECRP.. 䊚 2000 Elsevier Science B.V. All rights reserved. Keywords: Sputter coating; Inside coating of tube; ECR plasma; Magnetron plasma
1. Introduction
2. Coaxial magnetron pulsed plasma (CMPP)
Narrow tubes are widely used in industries as water pipes, gas pipes, cooling pipes for nuclear reactors, and so on. These tubes are often required to have better performances in corrosion and wear behaviors. It is necessary, therefore, to protect the inside of tubes. For the purpose, several investigations on inner coatings have been reported w1᎐7x. In our laboratory, plasma reactors have been developed by using magnetron hollow cathode discharges w8x, coaxial magnetron pulsed discharges ŽCMPP. w9᎐11x and coaxial electron cyclotron resonance discharges ŽCECRP. has been developed as reported in the previous article w12᎐15x. In the present paper, we report on the experimental results regarding discharge characteristics, plasma generations and thin film depositions on inner wall of narrow tubes using the CMPP and CECRP reactors.
2.1. Experimental
U
Tel.: q81-95-847-6437; fax: q81-95-847-6437. E-mail address: [email protected] ŽH. Fujiyama..
The CMPP device shown in Fig. 1 consists of a long cylindrical vacuum chamber, 50 mm in diameter and 1700 mm in length, a turbo molecular and rotary pumps for less than 10y6 torr in base pressure, water-cooled solenoid coils arranged coaxial around the chamber and pulse power supply. Glass tubes of 8 mm in inner diameter, 1 mm in thickness and 600 mm in length were set parallel to a cathode rod. Pulsed discharges were generated between a long cathode rod of 2 mm in diameter and 800 mm in length and a grounded short anode ring of 6 mm in the inner diameter and 5 mm in length. A strong uniform magnetic field was applied parallel to the cathode to increase the discharge current and decrease the operating gas pressure which were effective for high deposition rate and adhesion of the coated films. The target atoms were sputtered off and deposited onto the inner surface of glass tube. Typical experimental conditions were as follows: argon pressure Ps 30 mtorr, magnetic
0257-8972r00r$ - see front matter 䊚 2000 Elsevier Science B.V. All rights reserved. PII: S 0 2 5 7 - 8 9 7 2 Ž 0 0 . 0 0 8 0 1 - X
H. Fujiyama r Surface and Coatings Technology 131 (2000) 278᎐283
279
Fig. 1. Experimental setup of CMPP.
flux density B s 1050 G, negative pulse voltage VP s 1.5᎐2.5 kV, pulse repetitive frequency 1 kHz and pulse width s 10 s, i.e. the duty cycle of 1%. The axial distribution of film thickness was measured by a light absorption method. Relative film thickness can be estimated by FT s log e Ž I0rI x ., where I0 is the light ŽLED: GaAsP:N, center wavelength 630 nm, halfwidth 45 nm. intensity passed through a non-deposited area of a glass tube and I x is at measuring position of film thickness. 2.2. Results and discussions 2.2.1. Extended anode effect In order to coat films onto an inner surface of a long tube by sputtering, plasmas must be shifted along the tube. In the CMPP device, pulsed plasmas are shifted away from the anode automatically with deposition time. The reason is that the conductive films deposited near the native anode located at the tube end play a role of an anode, as a consequence, plasmas are generated to the inner part of the tube Žsee Fig. 2.. Thus, this phenomenon was named as extended anode effect. Axial distributions of titanium ŽTi., tungsten ŽW. and gold ŽAu. film thickness coated by the CMPP method were investigated as a parameter of deposition time for Ps 30 mtorr, B s 1050 G, VP s y2.5 kV, f s 1 kHz and s 10 s, respectively. Fig. 3 shows the results for Ti coating. In these experiments, the anode was located at X s 0 cm. It was clear that all distributions were wide with the deposition time because of the extended anode effect. Note that measured film thickness cannot be compared with the other film’s one because of the difference in the deposition time and the light absorption of films. Deposition times were changed in each
film material ŽTi: 60᎐120 s, W: 10᎐20 s, Au: 5᎐8 s. for convenience of the measurement of film thickness in the light absorption method. Here, in the case of Ti film, the deposition rate estimated from absolute film thickness was 95 nmrmin Ž0.16 nmrpulse. at 5 cm from the anode. 2.2.2. Shifting ¨ elocity The shifting plasmas were observed by optical emission spectroscopy w10x. Fig. 4 shows that the shifting velocities in the case of depositions of Ti, W and Au films for 30 mtorr, B s 1050 G, VP s y2.5 kV, f s 1 kHz and s 10 s. Sputtering yields of these materials Žatomsrion. are Ti: 0.51, W: 0.57, Au: 2.40 ŽArq, 500 eV. and resistivities Ž ⍀ m. are Ti: 47.0= 10y8 , W: 5.50= 10y8 , Au: 2.35= 10y8 Žat 293 K.. It was found
Fig. 2. Principle of the extended anode effect.
280
H. Fujiyama r Surface and Coatings Technology 131 (2000) 278᎐283
Fig. 4. Shifting velocities for various metallic films. Fig. 3. Axial distributions of Ti film thickness as a parameter of sputter᎐deposition time.
that the shifting velocity increased as sputtering yield was high and resistivity was low. Certain film thickness seems to be necessary for the appearance of the extended anode effect, so it is natural that the shifting velocity increases in the case of film materials which have high sputtering yield. Although Ti and W have nearly same sputtering yield, these shifting velocities were quite different. It may be caused by the difference of the resistivity. The shifting velocities which are normalized by sputtering yields increased with the decrease in resistivity of film material, because the film thickness required for the appearance of the extended anode effect becomes thinner as film resistivitly is lower. In short, the shifting velocity depends on the time up to which the deposited film can be anode.
3. Coaxial ECR plasma (CECRP) 3.1. Experimental The experimental setup is shown in Fig. 5. Plasmas were generated inside the tube by ECR which was possible to discharge at low pressures of less than 10y3 torr and narrow gap of several millimeters. Operational gases were pure Ar and N2rAr mixture for TiN reactive coatings. The base pressure of the vacuum chamber was less than 5 = 10y6 torr. Sputter target was a titanium rod Ž5 mm in diameter and 500 mm in length., and the substrate was a grounded stainless steel tube Ž30 mm in inner diameter and 480 mm in length. or an insulated glass tube Ž27 mm in inner diameter and 480 mm in length. which was inserted in a metallic tube. Microwave power was supplied by a magnetron at a frequency of 2.45 GHz and maximum continuous power
Fig. 5. Experimental setup of CECRP.
H. Fujiyama r Surface and Coatings Technology 131 (2000) 278᎐283
281
Fig. 6. Applied magnetic field pattern and their axial profiles by using mirror-type magnetic field.
of 200 W, and was transmitted in TEM mode which had no cutoff frequency. The coaxial cable and a coaxial tube as a target and the substrate were connected by a tapered tube to transform a diameter of outer conductor from 8 to 30 mm. Five solenoid coils were set around the process chamber at equal spaces apart. Magnetic field excited by the coils was controlled by using a computer and a switching regulator. It allows to scan the ECR points and transport plasma along the tube axis. For sputter coating, DC bias voltage was applied to the target. Mirror-type magnetic field was formed by switching on two coils. By using such a mirror-type magnetic field, we have succeeded in low-pressure discharge, high deposition rate and good uniformity of axial distribution of deposition rate in metallic tubes w15x. Mirror-type magnetic field can confine initial electrons within the ECR region. Fig. 6 shows the current switching pattern of two coils when the inner surface of tube should be coated all over. As the magnetic field for two coils can always be applied, it is possible to widely apply a magnetic field with several ECR points in the axial direction of the tube. Therefore, electron loss to the inner wall and axial direction of the tube can be decreased, and microwave power can be absorbed efficiently to the plasma.
for low pressure and low microwave incident power could be realized in the insulated glass tube. 3.2.2. Axial distribution of sputter deposition of insulated glass tube As the plasma position could be transported by using this control system of magnetic field, we performed Ti inner coating of the insulated glass tube. Current switching pattern of two coils was used by Coil Ž1.2. ᎐ Ž2.3. ᎐ Ž3.4. ᎐ Ž4.5. Žsee Fig. 6. and the deposition time was 5 min for each switching pattern. Here, Ar pressure P was 0.1 mtorr, the microwave incident power Pinc was 100 W, the target voltage Vt was y400 V, and the maximum magnetic flux density Bmax was 1020 G. The optical absorption method was used for the measurement of deposition rate. Fig. 8 shows the axial distribution of deposition rate in the insulated glass tube for each switching pattern. In each switching pattern, it was a little different in deposition rate. Especially, the deposition rate near the tube end apart from the microwave window was low. However, by
3.2. Results and discussions 3.2.1. Discharge characteristics Fig. 7 shows the discharge characteristics in insulated glass tube compared to that in metallic tubes. The plot shows the minimum microwave incident power for breakdown as a function of Ar pressure by using the mirror-type magnetic field for Coil 3 and 4. The electric field of microwave in discharge space increases by inserting the insulated glass tube in a metallic tube. Moreover, initial electrons for breakdown should be confined by negatively charged insulated glass surface. Although the discharge gap length of insulated glass tube is shorter than that of the metallic tube, discharge
Fig. 7. Discharge characteristics in the insulated glass tube compared to that in the metallic tube.
282
H. Fujiyama r Surface and Coatings Technology 131 (2000) 278᎐283
pressure Ptotal of 0.14 mtorr. The atomic composition ratio, NrTi, of the films was unity and almost homogeneous in the films. Although the oxygen contamination was so high, the deposited film showed a gold color.
4. Conclusions In order to coat thin films onto the inner surface of narrow tubes with high aspect ratios in length to inner diameter, we have developed a CMPP device. Using the extended anode effect, we have succeeded in coating a Ti thin film onto the inner surface of a narrow glass tube of 1000 mm in length and 8 mm in inner diameter in a double ended anode coaxial magnetron pulsed plasmas ŽDCMPP. device. In coaxial ECR plasmas, it was found that the electric field of microwave in insulated tube was increased, and the discharge for low pressure and low microwave incident power was realized by inserting insulated tubes into metallic tubes. The titanium films have been successfully coated on the inner wall of the glass tube of 27 mm in inner diameter and 480 mm in length by scanning the mirror-type ECR magnetic field. The present inner coating system was applied to reactive sputter deposition of TiN films, and the trial deposition was successfully performed by TiN inner coating of metallic tubes of 30 mm in inner diameter and 480 mm in length. Fig. 8. Axial distribution of deposition rate for each switching pattern in the insulated glass tube.
controlling the deposition time in each switching pattern, for example, the deposition time in Coil Ž4.5. is much longer, the coating uniformity might be able to verify.
3.2.3. Titanium nitride inner coating of metallic tube by reacti¨ e sputtering Titanium nitride ŽTiN. coatings have been used very successfully in a variety of applications because of their excellent properties, such as hard and anti-wear and good corrosion resistance w16x. So the present inner coating system was applied to a reactive sputter deposition of TiN films. The glass substrate Ž5 = 5 mm. was set in the metallic tube at the position z s 250 mm from the substrate edge Ž zs 0.. Plasma was generated inside the metallic tube by using mirror-type magnetic field for Coil 3 and 4, and the TiN films were deposited for 30 min for Ar flow rate of 0.1 sccm, N2 flow rate of 0.1 sccm and total
Acknowledgements The author would like to thank Dr H. Kuwahara, Dr K. Kuwahara, M. Morita, S. Sugimoto and T. Nagano for their technical help with the researches. This work was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science and Culture ŽKiban-BŽ2., 10558066.. References w1x Y. Matsuzawa, H. Yasuda, J. Appl. Polym. Sci., Appl. Polym. Symp. 38 Ž1984. 65. w2x T. Ihara, H.K. Yasuda, J. Appl. Polym. Sci., Appl. Polym. Symp. 46 Ž1990. 511. w3x J.A. Sheward, Surf. Coat. Technol. 54r55 Ž1992. 297. w4x R. Hytry, W. Moller, R. Wilhelm, A.V. Keudell, Vac. Sci. Technol. A11 Ž1993. 2508. w5x R. Hytry, W. Moller, R. Wilhelm, Surf. Coat. Technol. 74r75 Ž1995. 43. w6x W. Ensinger, Rev. Sci. Instrum. 67 Ž1996. 318. w7x W. Ensinger, Surf. Coat. Technol. 86r87 Ž1996. 438. w8x H. Kawasaki et al., Mater. Sci. Eng. A140 Ž1991. 682. w9x H. Fujiyama et al., Surf. Coat. Technol. 98 Ž1998. 1467.
H. Fujiyama r Surface and Coatings Technology 131 (2000) 278᎐283 w10x Y. Uchikawa et al., Thin Solid Films 112 Ž1999. 185. w11x S. Sugimoto et al., Jpn. J. Appl. Phys. 38 Ž1999. 4342. w12x T. Shigemizu, N. Ohno, H. Fujiyama, Mater. Sci. Eng. A139 Ž1991. 312. w13x H. Fujiyama, H. Kawasaki, T. Fujiyama, S. Takagi, Surf. Coat.
283
Technol. 59 Ž1993. 140. w14x E. Morisaki, H. Fujiyama, Surf. Coat. Technol. 98 Ž1997. 834. w15x E. Morisaki, T. Nagano, H. Fujiyama, Trans. IEE Jpn. Žin Japanese. 177-A Ž1997. 1207. w16x Y. Miyamoto et al., Thin Solid Films 270 Ž1995. 253.