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Tantalum film deposited by asymmetric a-c sputtering
204
ABSTRACTS ON MICROELECTRONICS AND RELIABILITY
on amorphous fused quartz substrates by cathodic sputtering in argon atmospheres. All As-sputtered films were found to have high electrical resistivities of about 104 fl-cm, despite controlled variation of the substrate temperature from 50° to 400°C. The high resistivity of the n-type films persisted even after post-deposition heat treatments as high as 1000°C, while p-type films showed a sharp decrease in resistivity to values on the order of 1 f~-cm or lower after heat treatments above 650°C. X-ray and electron diffraction, together with transmission electron microscopy of the p-type films, revealed that the improved electrical properties resulted from two distinct processes. A primary crystallization or recovery within the grains, which were approximately 200 A dia. in the As-sputtered films, accompanied the initial sharp drop in resistivity at 650°C. Following this process, a secondary recrystallization or discontinuous grain growth was nucleated in films heated at 1000°C. The resulting significantly increased size of certain grains and the corresponding decrease in grain boundary area accompanied an additional decrease in resistivity after heat treatment at 1000°C. Tantalum film deposited by asymmetric a-c sputtering. F. VRATNY and D. J. HARRINGTON,
.7. Electrochem. Soc., 112, No. 5, May (1966), p. 484. The new technique of asymmetric a-c sputtering has been evaluated for the deposition of Ta films in Ar, O f Ar, and N f A r gas mixtures. This method utilizes a lower sputtering potential on the Ta cathode.
Preparation and characterization of evaporated boron ~ m s . P. E. McELLIGOTTand R. W ROBIntTS,ju. Appl. Phys., 37 (1966), p. 1992. A method of preparing high purity, evaporated boron films by direct ohmic heating of elemental boron filaments in ultrahigh-vacuum is described. Deposition of g e r m a n i u m films by sputtering. K. E. HAQ, ft. Electrochem. Soc., 112, No. 5, May (1966), p. 500. Both n- and p-type germanium films were deposited epitaxially by using asymmetric a-c sputtering. The quantity of the films was found to be strongly dependent on the substrate temperature and the voltage during both the cleaning and the sputtering cycles.
Appl. Phys., 37, No. 2, February (1966), p. 574. Insulators cannot be sputtered with standard d.c. glow discharge techniques, because the accelerating potential cannot be directly applied and because the positive charge which accumulates on the surface during ion bombardment cannot be neutralized. Direct sputtering of insulators can be achieved by applying a high frequency potential to a metal electrode behind the dielectric target. This technique was used to deposit thin insulating films. D i e l e c t r i c thin filmA through r f sputtering. P. D. DAVmSEand L. I. MAIS~.L,ft.
Effect of ferroelectric polarization on insulated-gate thln-film transistor parameters. R. ZULmGand H. H. WmD~R,Solid St. Electron., 9 (1966), p. 657. The properties of a thin-film transistor deposited upon an oriented, ferroelectric triglycine sulfate (TGS) crystal have been evaluated in terms of the interaction between the remanent spontaneous polarization of the ferroelectric element and the space charge in the semiconductor layer. Experimental data suggests that this interaction results in changing the threshold voltage Vo for the onset of drain current. Precision thin-film resistors. E. STERN, Proc. 1966 Electronic Components Conf., Washington DC, p. 233. A technique is described which allows precision thin-film resistors to be fabricated without the necessity of individual trimming. This is achieved by bias sputtering of nickel-chromium films under carefully controlled conditions.
Advanced thln-film capacitor processes. J. R. CROWDERand L. W. NAIL, Proc. 1966 Electronic Components Conf., Washington DC, p. 313. This paper describes a process for the production of aluminium oxide capacitors in thin-film integrated circuits by anodization. The test information which characterizes these capacitors is presented. A survey of the physical properties of oxides, metals and substrate materials and the utilization of these properties for capacitor development is discussed. Processes for fabricating thin-film tantalum, zirconium and titanium oxide capacitors by vacuum deposition and anodization are described. Niobium oxide, tungsten oxide and hafnium dioxide as capacitor dielectric materials are considered.
ABSTRACTS ON MICROELECTRONICS AND RELIABILITY
on amorphous fused quartz substrates by cathodic sputtering in argon atmospheres. All As-sputtered films were found to have high electrical resistivities of about 104 fl-cm, despite controlled variation of the substrate temperature from 50° to 400°C. The high resistivity of the n-type films persisted even after post-deposition heat treatments as high as 1000°C, while p-type films showed a sharp decrease in resistivity to values on the order of 1 f~-cm or lower after heat treatments above 650°C. X-ray and electron diffraction, together with transmission electron microscopy of the p-type films, revealed that the improved electrical properties resulted from two distinct processes. A primary crystallization or recovery within the grains, which were approximately 200 A dia. in the As-sputtered films, accompanied the initial sharp drop in resistivity at 650°C. Following this process, a secondary recrystallization or discontinuous grain growth was nucleated in films heated at 1000°C. The resulting significantly increased size of certain grains and the corresponding decrease in grain boundary area accompanied an additional decrease in resistivity after heat treatment at 1000°C. Tantalum film deposited by asymmetric a-c sputtering. F. VRATNY and D. J. HARRINGTON,
.7. Electrochem. Soc., 112, No. 5, May (1966), p. 484. The new technique of asymmetric a-c sputtering has been evaluated for the deposition of Ta films in Ar, O f Ar, and N f A r gas mixtures. This method utilizes a lower sputtering potential on the Ta cathode.
Preparation and characterization of evaporated boron ~ m s . P. E. McELLIGOTTand R. W ROBIntTS,ju. Appl. Phys., 37 (1966), p. 1992. A method of preparing high purity, evaporated boron films by direct ohmic heating of elemental boron filaments in ultrahigh-vacuum is described. Deposition of g e r m a n i u m films by sputtering. K. E. HAQ, ft. Electrochem. Soc., 112, No. 5, May (1966), p. 500. Both n- and p-type germanium films were deposited epitaxially by using asymmetric a-c sputtering. The quantity of the films was found to be strongly dependent on the substrate temperature and the voltage during both the cleaning and the sputtering cycles.
Appl. Phys., 37, No. 2, February (1966), p. 574. Insulators cannot be sputtered with standard d.c. glow discharge techniques, because the accelerating potential cannot be directly applied and because the positive charge which accumulates on the surface during ion bombardment cannot be neutralized. Direct sputtering of insulators can be achieved by applying a high frequency potential to a metal electrode behind the dielectric target. This technique was used to deposit thin insulating films. D i e l e c t r i c thin filmA through r f sputtering. P. D. DAVmSEand L. I. MAIS~.L,ft.
Effect of ferroelectric polarization on insulated-gate thln-film transistor parameters. R. ZULmGand H. H. WmD~R,Solid St. Electron., 9 (1966), p. 657. The properties of a thin-film transistor deposited upon an oriented, ferroelectric triglycine sulfate (TGS) crystal have been evaluated in terms of the interaction between the remanent spontaneous polarization of the ferroelectric element and the space charge in the semiconductor layer. Experimental data suggests that this interaction results in changing the threshold voltage Vo for the onset of drain current. Precision thin-film resistors. E. STERN, Proc. 1966 Electronic Components Conf., Washington DC, p. 233. A technique is described which allows precision thin-film resistors to be fabricated without the necessity of individual trimming. This is achieved by bias sputtering of nickel-chromium films under carefully controlled conditions.
Advanced thln-film capacitor processes. J. R. CROWDERand L. W. NAIL, Proc. 1966 Electronic Components Conf., Washington DC, p. 313. This paper describes a process for the production of aluminium oxide capacitors in thin-film integrated circuits by anodization. The test information which characterizes these capacitors is presented. A survey of the physical properties of oxides, metals and substrate materials and the utilization of these properties for capacitor development is discussed. Processes for fabricating thin-film tantalum, zirconium and titanium oxide capacitors by vacuum deposition and anodization are described. Niobium oxide, tungsten oxide and hafnium dioxide as capacitor dielectric materials are considered.