- Email: [email protected]
Evaporation source with electron-bombardment heating for various applications
Classified
abstracts
790-801
energies reported for diffusivities are: Ne, 9.55 kcaljmole; Ar, 28.7 kcal/mole: and D,. 9.26 kcal/mole. Details of substrate preparation and material are given. W G Perkins and D R Begeal, J Chenz fhys, 54 (4). 15th Feb 197 I, I68331 694. 30 790. Epitaxial growth behaviour of Ge on Si (111) surfaces. (Germany) The morphology of Ge films evaporated on Si (I I I) surfaces has been investigated by electron diffraction and scanning microscopy. An ion and titanium sublimation pumped oil-free vacuum system was employed. Working background pressure was below I x IO-@ torr. Germanium deposition was performed from a conventional electrongun evaporator, using carbon or AI,O,, coated tantalum pedestals as support for the germanium evaporand. The silicon specimens used for substrates were chemically etched, transferred into the vacuum and cleaned by an anneal. Depending on the cleanness of the substrates, bulk epitaxial Ge or reconstructed Ge growth pyramids with (I I I) tops and (I 13) facets were observed respectively. For clean conditions, bulk Ge growth occurs at an epitaxial temperature of 59o’C. Formation of reconstructed crystals and an increase of the epitaxial temperature to 870°C is observed under identical experimental conditions during the presence of contaminations. Carbon impurities on the Si substrate resulting evidently from the evaporation source, are believed to be the cause for this latter growth behaviour. (USA) G 0 Krause, Phys Stat Sol (a). 3 (4). Dee 1970,907-9 II 30 791. Comparison of sputtering and evaporation. (Germany) Thin film deposition techniques using sputtering and evaporation are reviewed. The evaporation and sputtering rates for different materials are compared. S Schiller et al, Exper Tech Phys, 18 ( I -2), 1970, I I9- I34 (in German). 30 792. Intrinsic mechanical stress in evaporated thin films of nickelchromium alloy. (Germany) Construction of an arrangement for measurement of intrinsic mechanical stress in thin evaporated films is described. The intrinsic mechanical stress in nickel-chromium alloy thin films on mica substrates prepared by flash evaporation in vacuum at 5 x IO-’ torr is measured in vacuum as dependent on film thickness and composition. D Sternbeck, Exper Tech Phys, 18 (I-2). 1970, 105-108 (in Germcm). 30 793. Preparation, semiconducting properties and some applications of thin vapour-deposited films of some II-V compounds. (Germany) A review of the preparation, semiconducting properties and applications of thin vacuum deposited films of some II-V compounds is presented. The compounds of this intermetallic group are Zn,P,, Zn,As,, Cd,,P, and Cd,sAs,. Development of the appropriate technology for semiconducting compound film deposition in vacuum requires a very good knowledge of vapour pressure dependence on temperature for these materials and determination of conditions, in which the components evaporate in stoichiometric composition, in spite of thermal dissociation proceeding during the evaporation process. Dissociation of compound molecules occurs already in the surface layer of solid phase and the evaporation products do not appear in stoichiometric composition. However, for large area of the evaporation surface and at sufficiently high temperature, the material will evaporate in stoichiometric composition. Thin films of Cd:,As, and Zn,As, have been obtained by direct evaporation of bulk material in vacuum of the order of IO-” torr. Homogeneity of films can be corrected by suitable annealing of the deposits after their formation. Very promising electrical and good mechanical properties of Cd:,As, films deposited on substrates heated to 15617O’C permit their use as thin film Hall elements. (Poland) L Zdanowicz and W Zdanowicz, Eq~eu Tech Phys, 18 (3), 1970, 185197. 30 794. Some operational properties of a new high vacuum evaporation apparatus B55.2. (Germany) The new high vacuum evaporation apparatus is intended for application in electronic industry. It possesses a vertical deposition chamber with a diameter of 550 mm. The vacuum system is made of Cr-Ni steel and viton is used as gasket material. The pumping system consisting of a mechanical pump with pumping speed of 60 m3/hour and and oil diffusion pump with pumping speed of 2000 litres/sec permits short evacuation times. The pumping process can be controlled manually or automatically. Vacuum-chamber inner walls can be 360
heated to 2OO;C in 30 minutes. To improve the adhesion of evaporated films, the substrates can be cleaned by glow discharge before evaporation. Maximum discharge voltage is 3.2 kV and discharge current is 500 mA. Freezing traps of the Meissner type are used for efficient pumping of condensible vapours. Two evaporators, an electron-beam evaporation source and a multiple source, allow evaporation of complex compounds. Substrate temperature can be set up to 1000°C with precision of 1 deg. A pressure of 5 x IO-* torr is reached in the deposition chamber after 90 minutes of operation and, the operating pressure during resistive or electron-beam evaporation is 1 x lo-” torr. K Weber et al, E.uper Tech Phys, 18 ( I -2), 1970, 179-l 84 (in Gernran). 30 795. Recent developments in ion-sputtering. (Germany) Recent developments in plasma sputtering, ion-beam sputtering, charge compensation, reactive sputtering and bias sputtering are covered. Properties of thin layers obtained by sputtering are discussed. 0 Fielder, E.uper Tech Phys, 18 (l-2), 1970, 109-l 18 (in German). 30 796. Special applications of evaporators with horizontally positioned cylindrical bell jars. (Germany) An evaporator with a horizontally positioned cylindrical bell jar is described. The properties and advantages of this arrangement are compared with those of evaporators having vertically positioned cylindrical bell jars. S Schiller et al, Exper Tech PhJs, 18 (I-2). 1970, 169-l 78 (in German). 30 797. Film composition and evaporation behaviour of 80Ni/20Cr alloy. (Germany) Vacuum evaporated
films of Ni/Cr alloy are used as metallic film resistors. Properties of the film are dependent on the film composition. The film composition and the width of chromium in the wire diffussion zone are determined as function of the evaporation time. E Schippel, &per Tech Phys, 18 (I -2), 1970, 163-l 67 (in German). 30 798. Evaporation source with electron-bombardment heating for various applications. (Germany) An evaporation source with electron-bombardment heating is described in which the crucibles in the evaporator are changeable. An evaporation rate of 50 A/set is reached for metals. P Renner, E.rper Tech Phj,.v, 18 (I -2), 1970, 159-l 61 (i/r Russian). 30 799. Some problems of evaporation in ultrahigh vacuum. (Germany) Results of examination of an all-metal ultrahigh vacuum evaporation apparatus which permits deposition of semiconductors and insulators at pressures below IO-’ torr in the chamber, are reported. The evaporated films may be treated after deposition at residual gas pressure of a few 10-O torr in an ambient of reactive gas with a controlled pressure in the range 10m7 to lOma torr. It is found that with viton gaskets in the bell jar flange, a pressure of IO-‘” torr is reached in the bell jar after baking to IOO’C and using a pump with pumping speed of 2000 litres/sec. After degassing the evaporation sources, substrate holder and sublimation pump, and before baking, a pressure of 4 u IO-” torr is reached in the evaporator during CdSe evaporation. A quadrupole mass spectrometer is used for partial pressure analysis. It is found that on admission of oxygen to a pressure of lo-’ torr in the bell jar, the influence of the residual atmosphere was less than 3 x IO-” torr. W Meister, E.rper Tech P hys, 18 ( I -2), I 970, I4 I - I5 I (in Germm). 30 800. Induction heated evaporation source. (Germany) An induction heated evaporation source is described. A high frequency generator with power of 5 kW at frequency of 800 kHz is used. With a ceramic crucible, a temperature of 1700°C is reached, resulting in an evaporation rate of 100 Ajsec for nickel. V Walther et al, Exper Tech Phys, 18 (l-2). 1970, 153-158 (in German). 30 801. Electron-beam vacuum evaporation. (Germany) An arrangement for electron-beam vacuum evaporation is described which utilizes a fixed accelerating voltage of 18 kV and maximum beam power of 6 kW. The beam current can be set from zero to 380 mA. The electron gun which can be placed inside the bell jar or on the outside wall of the bell jar, contains a triode gun system, magnetic lens and coils for beam deflection. The tungsten cathode is heated by electron bombardment. The entire gun can be heated to 500°C for degassing. This is important for operation in ultrahigh vacuum condi-
abstracts
790-801
energies reported for diffusivities are: Ne, 9.55 kcaljmole; Ar, 28.7 kcal/mole: and D,. 9.26 kcal/mole. Details of substrate preparation and material are given. W G Perkins and D R Begeal, J Chenz fhys, 54 (4). 15th Feb 197 I, I68331 694. 30 790. Epitaxial growth behaviour of Ge on Si (111) surfaces. (Germany) The morphology of Ge films evaporated on Si (I I I) surfaces has been investigated by electron diffraction and scanning microscopy. An ion and titanium sublimation pumped oil-free vacuum system was employed. Working background pressure was below I x IO-@ torr. Germanium deposition was performed from a conventional electrongun evaporator, using carbon or AI,O,, coated tantalum pedestals as support for the germanium evaporand. The silicon specimens used for substrates were chemically etched, transferred into the vacuum and cleaned by an anneal. Depending on the cleanness of the substrates, bulk epitaxial Ge or reconstructed Ge growth pyramids with (I I I) tops and (I 13) facets were observed respectively. For clean conditions, bulk Ge growth occurs at an epitaxial temperature of 59o’C. Formation of reconstructed crystals and an increase of the epitaxial temperature to 870°C is observed under identical experimental conditions during the presence of contaminations. Carbon impurities on the Si substrate resulting evidently from the evaporation source, are believed to be the cause for this latter growth behaviour. (USA) G 0 Krause, Phys Stat Sol (a). 3 (4). Dee 1970,907-9 II 30 791. Comparison of sputtering and evaporation. (Germany) Thin film deposition techniques using sputtering and evaporation are reviewed. The evaporation and sputtering rates for different materials are compared. S Schiller et al, Exper Tech Phys, 18 ( I -2), 1970, I I9- I34 (in German). 30 792. Intrinsic mechanical stress in evaporated thin films of nickelchromium alloy. (Germany) Construction of an arrangement for measurement of intrinsic mechanical stress in thin evaporated films is described. The intrinsic mechanical stress in nickel-chromium alloy thin films on mica substrates prepared by flash evaporation in vacuum at 5 x IO-’ torr is measured in vacuum as dependent on film thickness and composition. D Sternbeck, Exper Tech Phys, 18 (I-2). 1970, 105-108 (in Germcm). 30 793. Preparation, semiconducting properties and some applications of thin vapour-deposited films of some II-V compounds. (Germany) A review of the preparation, semiconducting properties and applications of thin vacuum deposited films of some II-V compounds is presented. The compounds of this intermetallic group are Zn,P,, Zn,As,, Cd,,P, and Cd,sAs,. Development of the appropriate technology for semiconducting compound film deposition in vacuum requires a very good knowledge of vapour pressure dependence on temperature for these materials and determination of conditions, in which the components evaporate in stoichiometric composition, in spite of thermal dissociation proceeding during the evaporation process. Dissociation of compound molecules occurs already in the surface layer of solid phase and the evaporation products do not appear in stoichiometric composition. However, for large area of the evaporation surface and at sufficiently high temperature, the material will evaporate in stoichiometric composition. Thin films of Cd:,As, and Zn,As, have been obtained by direct evaporation of bulk material in vacuum of the order of IO-” torr. Homogeneity of films can be corrected by suitable annealing of the deposits after their formation. Very promising electrical and good mechanical properties of Cd:,As, films deposited on substrates heated to 15617O’C permit their use as thin film Hall elements. (Poland) L Zdanowicz and W Zdanowicz, Eq~eu Tech Phys, 18 (3), 1970, 185197. 30 794. Some operational properties of a new high vacuum evaporation apparatus B55.2. (Germany) The new high vacuum evaporation apparatus is intended for application in electronic industry. It possesses a vertical deposition chamber with a diameter of 550 mm. The vacuum system is made of Cr-Ni steel and viton is used as gasket material. The pumping system consisting of a mechanical pump with pumping speed of 60 m3/hour and and oil diffusion pump with pumping speed of 2000 litres/sec permits short evacuation times. The pumping process can be controlled manually or automatically. Vacuum-chamber inner walls can be 360
heated to 2OO;C in 30 minutes. To improve the adhesion of evaporated films, the substrates can be cleaned by glow discharge before evaporation. Maximum discharge voltage is 3.2 kV and discharge current is 500 mA. Freezing traps of the Meissner type are used for efficient pumping of condensible vapours. Two evaporators, an electron-beam evaporation source and a multiple source, allow evaporation of complex compounds. Substrate temperature can be set up to 1000°C with precision of 1 deg. A pressure of 5 x IO-* torr is reached in the deposition chamber after 90 minutes of operation and, the operating pressure during resistive or electron-beam evaporation is 1 x lo-” torr. K Weber et al, E.uper Tech Phys, 18 ( I -2), 1970, 179-l 84 (in Gernran). 30 795. Recent developments in ion-sputtering. (Germany) Recent developments in plasma sputtering, ion-beam sputtering, charge compensation, reactive sputtering and bias sputtering are covered. Properties of thin layers obtained by sputtering are discussed. 0 Fielder, E.uper Tech Phys, 18 (l-2), 1970, 109-l 18 (in German). 30 796. Special applications of evaporators with horizontally positioned cylindrical bell jars. (Germany) An evaporator with a horizontally positioned cylindrical bell jar is described. The properties and advantages of this arrangement are compared with those of evaporators having vertically positioned cylindrical bell jars. S Schiller et al, Exper Tech PhJs, 18 (I-2). 1970, 169-l 78 (in German). 30 797. Film composition and evaporation behaviour of 80Ni/20Cr alloy. (Germany) Vacuum evaporated
films of Ni/Cr alloy are used as metallic film resistors. Properties of the film are dependent on the film composition. The film composition and the width of chromium in the wire diffussion zone are determined as function of the evaporation time. E Schippel, &per Tech Phys, 18 (I -2), 1970, 163-l 67 (in German). 30 798. Evaporation source with electron-bombardment heating for various applications. (Germany) An evaporation source with electron-bombardment heating is described in which the crucibles in the evaporator are changeable. An evaporation rate of 50 A/set is reached for metals. P Renner, E.rper Tech Phj,.v, 18 (I -2), 1970, 159-l 61 (i/r Russian). 30 799. Some problems of evaporation in ultrahigh vacuum. (Germany) Results of examination of an all-metal ultrahigh vacuum evaporation apparatus which permits deposition of semiconductors and insulators at pressures below IO-’ torr in the chamber, are reported. The evaporated films may be treated after deposition at residual gas pressure of a few 10-O torr in an ambient of reactive gas with a controlled pressure in the range 10m7 to lOma torr. It is found that with viton gaskets in the bell jar flange, a pressure of IO-‘” torr is reached in the bell jar after baking to IOO’C and using a pump with pumping speed of 2000 litres/sec. After degassing the evaporation sources, substrate holder and sublimation pump, and before baking, a pressure of 4 u IO-” torr is reached in the evaporator during CdSe evaporation. A quadrupole mass spectrometer is used for partial pressure analysis. It is found that on admission of oxygen to a pressure of lo-’ torr in the bell jar, the influence of the residual atmosphere was less than 3 x IO-” torr. W Meister, E.rper Tech P hys, 18 ( I -2), I 970, I4 I - I5 I (in Germm). 30 800. Induction heated evaporation source. (Germany) An induction heated evaporation source is described. A high frequency generator with power of 5 kW at frequency of 800 kHz is used. With a ceramic crucible, a temperature of 1700°C is reached, resulting in an evaporation rate of 100 Ajsec for nickel. V Walther et al, Exper Tech Phys, 18 (l-2). 1970, 153-158 (in German). 30 801. Electron-beam vacuum evaporation. (Germany) An arrangement for electron-beam vacuum evaporation is described which utilizes a fixed accelerating voltage of 18 kV and maximum beam power of 6 kW. The beam current can be set from zero to 380 mA. The electron gun which can be placed inside the bell jar or on the outside wall of the bell jar, contains a triode gun system, magnetic lens and coils for beam deflection. The tungsten cathode is heated by electron bombardment. The entire gun can be heated to 500°C for degassing. This is important for operation in ultrahigh vacuum condi-