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New application for Se-Ge glasses to silicon microfabrication technology
The effect of film thickness on certain properties of Cr-SiO cermet thin films Electron. TechnoL, 10(1), p. 117 (1977). Results are discussed of the investigations of the effect of film thickness on density, resistivity, sheet resistivity and adhesion of the cermet thin films (50%-Cr, 50%-SIO composition) as well as of this effect on annealing coefficient and temperature coefficient of resistance of resistors manufactured from these films. The investigations were performed in the thickness range from about 180Ato about 1430A •
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Materials selection in hybrid product design R. D. GOLD SolidState Technology, p.31 (Jan. 1977). The materials used in a line of power hybrid voltage regulators and over-voltage protection modules have been selected for optimum performance, reliability, and econonly. The materials include steel, copper, nickel, brass, solder, glass-filled plastic, and epoxies, in addition to the usual pastes and ceramics used in hybrids• These materials, as used in these products, provide the proper combination of electrical, mechanical and thermal properties, and economy. Palladium-silver conductor paste has been found to be economical and reliable as a solderable conductor under high temperature service conditions, when used with a tin-free, lead-silver-indium solder. In the manufacture of these products, furnace assembly fixtures made of aluminium with stainless steel inserts can provide the optimum combination of thermal, mechanical, and durability properties.
7.
Production and Processing
Thermal oxidation of GaAs F. K O S H I G A and T. SUGANO PrOceedings of the 8th Conference (1976 International) on Solid State Devices, Tokyo, 1976; Japanese Journal of Applied Physics, 16, Supplement 16-1, pp.465-469 (1977).
Thermal oxidation of GaAs has been carried out for temperature range between 470°C and 830°C in dry and wet atmosphere. The experimental results show that the oxidation rate and the properties of the oxide film are dependent on the surface orientation and surface treatment of the wafers and the oxidation condition. For temperature range between 470~C and 530°C the oxidation follows the linear oxidation relationship for wafers with (111), (110) and (100) surface etched by HF, and the oxide dissolves in H F solution. The activation energy of the rate constant is 2.2eV, while the oxidation of the wafers with (100) surface dipped into methanol just before the oxidation follows the parabolic relationship and the oxide dissolves in boiling HCi. Liquid phase epitaxy apparatus for multiple layers utilislng centrifugal forces E. B A U S E R , L. SCHMIDT, K. S. LOECHNER and E. RAABE Proceedings of the 8th Conference (1976 International) on Solid State Devices, Tokyo, 1976; Japanese Journal of Applied Physics, 16, Supplement 16-I, pp.457-460 (1977). A liquid-phase epitaxy apparatus is described for growing very thin layers and multiple layers of compound semiconductors. The layers are deposited from flowing solutions. Both admittance of solution to the substrate and complete removal from the grown layer are very fast. There are no sliding parts next to the substrate, but retainment and release of solution flow is governed by surface tension and centrifugal force. After growth of each layer, the solution is recycled to its supply reservoir from which the epitaxy crucible is fed. Sound velocity in amorphous Ge and Si L. R. TESTARDI andJ. J. H A U S E R Solid State Communications, 2 I, p. 1039 (1977). The low frequency velocity of sound for a Young's modulus mode in sputtered amorphous films of Ge and Si is found to be only --55-60% of the value expected for the crystalline state. The reduction is one of the largest associated with crystalline-amorphous polymorphs. Reduced lateral diffusion and reverse leakage in Be-implanted
GaAsl-xPx diodes P. K. C H A q T E R J E E and B. G. STREETMAN
Solid State Electronics, 2, p.305 (1977). Lateral Z n diffusion under the SiaN4 mask encountered in standard red GaAs0.oP0. 4 light emitting diodes can be eliminated in Be-implanted
junctions. Typical reverse leakage current for implanted devices is --5nA compared with --250nA for Zn-diffused diodes. New application for Se-Ge glasses to silicon microfabrication technology A. YOSHIKAWA, H. N A G A I and Y. MIZUSHIMA Proceedings of the 8th Conference (1976 International) on Solid State Devices, Tokyo, 1976; Japanese Journal of Applied Physics, 16, Supplement 16-1, pp.67-71 (1977). A novel inorganic photoresist using Se-Ge glass films is proposed. Fundamental functions of this photoresist are based upon two types of distinct changes in the chemical solubility induced by irradiation of light. One of those is a phenomenon that the light exposure increases dissolution rate in alkaline solutions (positive type), and the other that chalcogenide glasses become almost insoluble into alkaline solutions by photodoping of silver (negative type). Suitable processing techniques and exposure characteristics are investigated. It is shown that the Se-Ge glass films can be used as a positive- or a negative-type photoresist by a slight change in the process of photoetching and that fine pattern photoetching of less than l p m linewidth in SiO2 is easily achieved. This photoresist has many potential advantages in high resolution, contrast, etch resistance and its processings.
~rnely uniform thin films by vacuum deposition from a 'tube source' H. S C H W A R T Z and U. L• de CASTRO Vacuum, 27(3), p.167 (1977). A vacuum deposition device without moving parts called 'tube source' has been developed which is capable of producing from a small area source on plane extended fixed substrates thin films with 10 times less thickness variation than a film would show deposited from the same small area source as the one used with the 'tube source' at the same distance but without the tube source arrangement. For exam'ple, using the tube source, a fiim deposited on a flat circular substrate of 10.4cm diameter shows a thickness varition less than -)'0.4% at a substrate to source distance of 23.2cm. The tube source.consists of a wide cylinder. A t one end on the axis of the cylinder there is a small area source, for example, a 1/2 inch commercial dimple boat electrically heated and filled with the material to be deposited; from the other end flat substrates were positioned in a plane perpendicular to the cylinder axis at varying distances. A disc with its plane also perpendicular to the axis and its centre on it was suspended with three very thin stretched wires inside the tube in such a way that no vapour atoms could hit the substrate directly, in other words the disc forms a shadow for the source on the substrate. Hereby, the arrival of vapour atoms can be made much more random depending on ihe geometry (distance of substrate from top end plane of cylinder, distance of source from bottom end plane, a.o.). The tube could be heated by nichrome wire wrapped around it to change the reflectivity of the vapour atoms. Optimum thickness distributions on the substrate were determined by Monte Carlo methods using a computer as well as analytically. Effect of heat treatment on chemical and electronic structure of solid SiO; an electron spectroscopy study G. HOLLINGER, Y. J U G N E T and T. M. DUC Solid State Communications, 22, p.277 (1977). Photoelectron spectroscopy (XPS and UPS) and X-ray excited Auger electron spectroscopy (XAES) measurements for commercial SiO powder and for SiO thin films show direct evidence for the evolution of the chemical structure of SiO from a characteristic metastable phase to a microscopic mixture of Si and SiOz when the temperature increases.
8. Testing A numerical analysis of various cross sheet resistor test structures J. M. D A V I D and M. G. B U E H L E R Solid State Electronics, 20, p.539 (1977). Various four-terminal cross sheet resistor test structures were analysed to determine the effect of the contact arm width and length on the measured sheet resistance. A nine-point fnite difference approximation to the Laplace equation was used with a six-resistor equivalent circuit to solve for the sheet resistance measurement error. The error indicates the difference between the true sheet resistance and the sheet resistance calculated from the van der Pauw formula. The analysis demonstrates that many noyel designs are possible. In particular, the Greek-cross sheet resistor is a valid van der Pauw test structure if the
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Materials selection in hybrid product design R. D. GOLD SolidState Technology, p.31 (Jan. 1977). The materials used in a line of power hybrid voltage regulators and over-voltage protection modules have been selected for optimum performance, reliability, and econonly. The materials include steel, copper, nickel, brass, solder, glass-filled plastic, and epoxies, in addition to the usual pastes and ceramics used in hybrids• These materials, as used in these products, provide the proper combination of electrical, mechanical and thermal properties, and economy. Palladium-silver conductor paste has been found to be economical and reliable as a solderable conductor under high temperature service conditions, when used with a tin-free, lead-silver-indium solder. In the manufacture of these products, furnace assembly fixtures made of aluminium with stainless steel inserts can provide the optimum combination of thermal, mechanical, and durability properties.
7.
Production and Processing
Thermal oxidation of GaAs F. K O S H I G A and T. SUGANO PrOceedings of the 8th Conference (1976 International) on Solid State Devices, Tokyo, 1976; Japanese Journal of Applied Physics, 16, Supplement 16-1, pp.465-469 (1977).
Thermal oxidation of GaAs has been carried out for temperature range between 470°C and 830°C in dry and wet atmosphere. The experimental results show that the oxidation rate and the properties of the oxide film are dependent on the surface orientation and surface treatment of the wafers and the oxidation condition. For temperature range between 470~C and 530°C the oxidation follows the linear oxidation relationship for wafers with (111), (110) and (100) surface etched by HF, and the oxide dissolves in H F solution. The activation energy of the rate constant is 2.2eV, while the oxidation of the wafers with (100) surface dipped into methanol just before the oxidation follows the parabolic relationship and the oxide dissolves in boiling HCi. Liquid phase epitaxy apparatus for multiple layers utilislng centrifugal forces E. B A U S E R , L. SCHMIDT, K. S. LOECHNER and E. RAABE Proceedings of the 8th Conference (1976 International) on Solid State Devices, Tokyo, 1976; Japanese Journal of Applied Physics, 16, Supplement 16-I, pp.457-460 (1977). A liquid-phase epitaxy apparatus is described for growing very thin layers and multiple layers of compound semiconductors. The layers are deposited from flowing solutions. Both admittance of solution to the substrate and complete removal from the grown layer are very fast. There are no sliding parts next to the substrate, but retainment and release of solution flow is governed by surface tension and centrifugal force. After growth of each layer, the solution is recycled to its supply reservoir from which the epitaxy crucible is fed. Sound velocity in amorphous Ge and Si L. R. TESTARDI andJ. J. H A U S E R Solid State Communications, 2 I, p. 1039 (1977). The low frequency velocity of sound for a Young's modulus mode in sputtered amorphous films of Ge and Si is found to be only --55-60% of the value expected for the crystalline state. The reduction is one of the largest associated with crystalline-amorphous polymorphs. Reduced lateral diffusion and reverse leakage in Be-implanted
GaAsl-xPx diodes P. K. C H A q T E R J E E and B. G. STREETMAN
Solid State Electronics, 2, p.305 (1977). Lateral Z n diffusion under the SiaN4 mask encountered in standard red GaAs0.oP0. 4 light emitting diodes can be eliminated in Be-implanted
junctions. Typical reverse leakage current for implanted devices is --5nA compared with --250nA for Zn-diffused diodes. New application for Se-Ge glasses to silicon microfabrication technology A. YOSHIKAWA, H. N A G A I and Y. MIZUSHIMA Proceedings of the 8th Conference (1976 International) on Solid State Devices, Tokyo, 1976; Japanese Journal of Applied Physics, 16, Supplement 16-1, pp.67-71 (1977). A novel inorganic photoresist using Se-Ge glass films is proposed. Fundamental functions of this photoresist are based upon two types of distinct changes in the chemical solubility induced by irradiation of light. One of those is a phenomenon that the light exposure increases dissolution rate in alkaline solutions (positive type), and the other that chalcogenide glasses become almost insoluble into alkaline solutions by photodoping of silver (negative type). Suitable processing techniques and exposure characteristics are investigated. It is shown that the Se-Ge glass films can be used as a positive- or a negative-type photoresist by a slight change in the process of photoetching and that fine pattern photoetching of less than l p m linewidth in SiO2 is easily achieved. This photoresist has many potential advantages in high resolution, contrast, etch resistance and its processings.
~rnely uniform thin films by vacuum deposition from a 'tube source' H. S C H W A R T Z and U. L• de CASTRO Vacuum, 27(3), p.167 (1977). A vacuum deposition device without moving parts called 'tube source' has been developed which is capable of producing from a small area source on plane extended fixed substrates thin films with 10 times less thickness variation than a film would show deposited from the same small area source as the one used with the 'tube source' at the same distance but without the tube source arrangement. For exam'ple, using the tube source, a fiim deposited on a flat circular substrate of 10.4cm diameter shows a thickness varition less than -)'0.4% at a substrate to source distance of 23.2cm. The tube source.consists of a wide cylinder. A t one end on the axis of the cylinder there is a small area source, for example, a 1/2 inch commercial dimple boat electrically heated and filled with the material to be deposited; from the other end flat substrates were positioned in a plane perpendicular to the cylinder axis at varying distances. A disc with its plane also perpendicular to the axis and its centre on it was suspended with three very thin stretched wires inside the tube in such a way that no vapour atoms could hit the substrate directly, in other words the disc forms a shadow for the source on the substrate. Hereby, the arrival of vapour atoms can be made much more random depending on ihe geometry (distance of substrate from top end plane of cylinder, distance of source from bottom end plane, a.o.). The tube could be heated by nichrome wire wrapped around it to change the reflectivity of the vapour atoms. Optimum thickness distributions on the substrate were determined by Monte Carlo methods using a computer as well as analytically. Effect of heat treatment on chemical and electronic structure of solid SiO; an electron spectroscopy study G. HOLLINGER, Y. J U G N E T and T. M. DUC Solid State Communications, 22, p.277 (1977). Photoelectron spectroscopy (XPS and UPS) and X-ray excited Auger electron spectroscopy (XAES) measurements for commercial SiO powder and for SiO thin films show direct evidence for the evolution of the chemical structure of SiO from a characteristic metastable phase to a microscopic mixture of Si and SiOz when the temperature increases.
8. Testing A numerical analysis of various cross sheet resistor test structures J. M. D A V I D and M. G. B U E H L E R Solid State Electronics, 20, p.539 (1977). Various four-terminal cross sheet resistor test structures were analysed to determine the effect of the contact arm width and length on the measured sheet resistance. A nine-point fnite difference approximation to the Laplace equation was used with a six-resistor equivalent circuit to solve for the sheet resistance measurement error. The error indicates the difference between the true sheet resistance and the sheet resistance calculated from the van der Pauw formula. The analysis demonstrates that many noyel designs are possible. In particular, the Greek-cross sheet resistor is a valid van der Pauw test structure if the
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