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Bi-CMOS: combination circuit offers economy and power
658
World Abstracts on Microelectronics and Reliability
become increasingly popular in the last few years but its applications have become more diversified. Its applications have grown in not only computers and communication systems but household appliance as well. It appears that ASIC is being applied universally to all technologies. Curve tracers advance MOSFET technology. KEN DIERBERGER. Semiconductor int., 88 (February 1988). Now capable of being programmed, the curve tracer has accelerated development of a revolutionary MOSFET power device. One-chip microcomputer creates new features in the consumer electronic industry. KOJIRO KURASHXMA.d. Electron. Enong Japan, 44 (April 1988). The one-chip microcomputer has grown from 4 bits to 16 bits, expanding its potential applications with increased performance and multifunctional capabilities. R&D of three dimensional circuit device getting to the final stage. KAZUYUKISUGAWARA.J. Electron. Engno Japan, 32
7. S E M I C O N D U C T O R
INTEGRATED
Bidirectional blocking junctions in SOI. BERNARD A. MACIVER, KAILASH C. JAIN and STEPHEN J. VALERI. I E E E Circuits Devices Mag., 27 (November 1987). Back-to-back junction (npn) structures were fabricated in silicon-onsapphire (SOS), in polysilicon-on-SiO2, and in siliconon-insulator (SOI) prepared by high-dose oxygen ion implantation. Since the structure is actually a bipolar transistor operated with an open base, the geometry and doping levels were adjusted to spoil its gain and thereby achieve symmetrical bidirectional blocking. In all three cases, ideal plane-junction breakdown was observed for both polarities of applied voltage when precautions were taken to avoid local field enhancing geometries. Removal processes for damage and contamination after CF4/40~oH 2 reactive ion etching of silicon. AWATARSINGH. Microelectron. J. 18(5), 13 (1987). State of the art of RIE reactors, nature of damage and contamination introduced, their effects and controls is briefly reviewed. The defect model as conceived on this basis is presented. The highly selective etching of SiO2 relative to Si is done by reactive ion etching with CF4/40~oH2. The damage and contamination introduced in Si are characterised by A1/p-Si Schottky diodes fabricated on dry etched Si wafers. The dry etching is found to convert an A1/p-Si ohmic contact into a rectifying one. Various removal processes of damage and contamination after dry etching are tried to restore the original behaviour of the diodes. The results indicate that ashing, (RF sputter etching in N2 ambient) followed by HF dip are sufficient to restore the surface. The effects of omissions of RF sputter etching in N2 ambient and HF dip are also discussed. An alternative process of thermal oxidation of dry etched Si wafers in an O2/TCE ambient at 10000C for 15 min followed by HF dip is also seen to recover the surface. This is confirmed by lifetime studies made on post-oxidised Si wafers. The latter process consumes more silicon. The suitability of the process for VLSI fabrication is also discussed. A new boron implantation model suitable for analytical modeling of threshold voltage of MOSFETS. A. DAS GUPTA and S. K. LAH1RI. Solid-St. Electron. 30, 1283 (1987). The boron implantation profile in silicon is usually simulated by the Pearson-IV distribution function with some modifications, as in SUPREM. But this function is complex from the point of view of analytical modeling. New functions which fit very well with SUPREM simulated implantation
(April 1988). Major companies have begun to look at this promising technology that could increase processing speed and integration of existing two dimension circuits. Bi-CMOS: combination circuit offers economy and power. Yozo TANIHARA.d. Electron. Engno Japan, 28 (April 1988). As equipment speed increased from the minicomputer to the personal computer, a strong demand arose for a device that combined speed and high integration; the Bi-CMOS answered that need. Gallium arsenide ICs promising as fast ICs in the highfrequency range. MASAHIRO HAGIO. J. Electron. Engng Japan, 36 (April 1988). Broadcasting, business communications and other communication systems are using satellites every day at the consumer level. Gallium arsenide (GaAs) devices, which contributed to the popularization of satellite communication systems, are now in the limelight. A particularly bright future is seen for GaAs ICs as highfrequency range, high-speed circuits exceeding the limits of their silicon counterparts.
CIRCUITS,
DEVICES
AND MATERIALS
profiles for boron in silicon have been proposed in this paper. These functions, being analytically integrable, allow us to formulate accurate analytical models of threshold voltages of MOSFETs with implanted channels. In this paper models for the threshold voltages of both long channel and short channel NMOSFETs have been presented. For the long channel case, the results agree very well with those obtained from numerical computations with considerable saving of computation time. The results of the short channel model also show good agreement with available experimental data. Laser annealing of GaAs implanted with low doses of selenium ions. J. A. AKINTUNDE. Solid-St. Electron. 30, 1251 (1987). GaAs samples were implanted with t00-400keV, 10t~-10~4/cm2 Se + ions and annealed using undiffused and diffused pulsed ruby-laser beams with the samples held at various temperatures. The resulting surface and structural defects as observed by various microscopic and spectroscopic methods are related to measured electrical properties of implanted GaAs, and the causes of the observed poor and lack of electrical activation of samples identified. Laser irradiation of samples (T ~ 516°C) induces surface damage in the form of regular parallel broken lines with a periodicity of about 0.69/~m, the wavelength of the ruby laser. A diffused laser beam (~< 0.5J/cm 2) reduces surface vaporisation and eliminates periodic surface structures. The measured electrical properties are still poor. Total-dose effects of gamma-ray irradiation on CMOS/ SIMOX devices. TERUKAZU OHNO, KATSUTOSHI [ZUMI, MASAKAZU SHIMAYAand NOSORU SHIONO. I E E E Circuits Devices Mag., 21 (November 1987). Radiation-hardened CMOS/SIMOX devices have been developed using a combination of vertical isolation structures obtained by SIMOX technology and newly developed lateral isolation structures. The n-channel MOSFET is vertically isolated by multilayers of highly oxygen-doped polysilicon and buried SiO2, and is laterally isolated by multilayers of thin sidewall SiO 2, sidewall polysilicon, and thick field SiO2. The p-channel MOSFET has the same vertical isolation structure as that of the n-channel MOSFET. However, it has no sidewall polysilicon layer but uses a thick field SiO 2 layer for lateral isolation. Highly oxygen-doped polysilicon and sidewall polysilicon layers act to shield radiation-
World Abstracts on Microelectronics and Reliability
become increasingly popular in the last few years but its applications have become more diversified. Its applications have grown in not only computers and communication systems but household appliance as well. It appears that ASIC is being applied universally to all technologies. Curve tracers advance MOSFET technology. KEN DIERBERGER. Semiconductor int., 88 (February 1988). Now capable of being programmed, the curve tracer has accelerated development of a revolutionary MOSFET power device. One-chip microcomputer creates new features in the consumer electronic industry. KOJIRO KURASHXMA.d. Electron. Enong Japan, 44 (April 1988). The one-chip microcomputer has grown from 4 bits to 16 bits, expanding its potential applications with increased performance and multifunctional capabilities. R&D of three dimensional circuit device getting to the final stage. KAZUYUKISUGAWARA.J. Electron. Engno Japan, 32
7. S E M I C O N D U C T O R
INTEGRATED
Bidirectional blocking junctions in SOI. BERNARD A. MACIVER, KAILASH C. JAIN and STEPHEN J. VALERI. I E E E Circuits Devices Mag., 27 (November 1987). Back-to-back junction (npn) structures were fabricated in silicon-onsapphire (SOS), in polysilicon-on-SiO2, and in siliconon-insulator (SOI) prepared by high-dose oxygen ion implantation. Since the structure is actually a bipolar transistor operated with an open base, the geometry and doping levels were adjusted to spoil its gain and thereby achieve symmetrical bidirectional blocking. In all three cases, ideal plane-junction breakdown was observed for both polarities of applied voltage when precautions were taken to avoid local field enhancing geometries. Removal processes for damage and contamination after CF4/40~oH 2 reactive ion etching of silicon. AWATARSINGH. Microelectron. J. 18(5), 13 (1987). State of the art of RIE reactors, nature of damage and contamination introduced, their effects and controls is briefly reviewed. The defect model as conceived on this basis is presented. The highly selective etching of SiO2 relative to Si is done by reactive ion etching with CF4/40~oH2. The damage and contamination introduced in Si are characterised by A1/p-Si Schottky diodes fabricated on dry etched Si wafers. The dry etching is found to convert an A1/p-Si ohmic contact into a rectifying one. Various removal processes of damage and contamination after dry etching are tried to restore the original behaviour of the diodes. The results indicate that ashing, (RF sputter etching in N2 ambient) followed by HF dip are sufficient to restore the surface. The effects of omissions of RF sputter etching in N2 ambient and HF dip are also discussed. An alternative process of thermal oxidation of dry etched Si wafers in an O2/TCE ambient at 10000C for 15 min followed by HF dip is also seen to recover the surface. This is confirmed by lifetime studies made on post-oxidised Si wafers. The latter process consumes more silicon. The suitability of the process for VLSI fabrication is also discussed. A new boron implantation model suitable for analytical modeling of threshold voltage of MOSFETS. A. DAS GUPTA and S. K. LAH1RI. Solid-St. Electron. 30, 1283 (1987). The boron implantation profile in silicon is usually simulated by the Pearson-IV distribution function with some modifications, as in SUPREM. But this function is complex from the point of view of analytical modeling. New functions which fit very well with SUPREM simulated implantation
(April 1988). Major companies have begun to look at this promising technology that could increase processing speed and integration of existing two dimension circuits. Bi-CMOS: combination circuit offers economy and power. Yozo TANIHARA.d. Electron. Engno Japan, 28 (April 1988). As equipment speed increased from the minicomputer to the personal computer, a strong demand arose for a device that combined speed and high integration; the Bi-CMOS answered that need. Gallium arsenide ICs promising as fast ICs in the highfrequency range. MASAHIRO HAGIO. J. Electron. Engng Japan, 36 (April 1988). Broadcasting, business communications and other communication systems are using satellites every day at the consumer level. Gallium arsenide (GaAs) devices, which contributed to the popularization of satellite communication systems, are now in the limelight. A particularly bright future is seen for GaAs ICs as highfrequency range, high-speed circuits exceeding the limits of their silicon counterparts.
CIRCUITS,
DEVICES
AND MATERIALS
profiles for boron in silicon have been proposed in this paper. These functions, being analytically integrable, allow us to formulate accurate analytical models of threshold voltages of MOSFETs with implanted channels. In this paper models for the threshold voltages of both long channel and short channel NMOSFETs have been presented. For the long channel case, the results agree very well with those obtained from numerical computations with considerable saving of computation time. The results of the short channel model also show good agreement with available experimental data. Laser annealing of GaAs implanted with low doses of selenium ions. J. A. AKINTUNDE. Solid-St. Electron. 30, 1251 (1987). GaAs samples were implanted with t00-400keV, 10t~-10~4/cm2 Se + ions and annealed using undiffused and diffused pulsed ruby-laser beams with the samples held at various temperatures. The resulting surface and structural defects as observed by various microscopic and spectroscopic methods are related to measured electrical properties of implanted GaAs, and the causes of the observed poor and lack of electrical activation of samples identified. Laser irradiation of samples (T ~ 516°C) induces surface damage in the form of regular parallel broken lines with a periodicity of about 0.69/~m, the wavelength of the ruby laser. A diffused laser beam (~< 0.5J/cm 2) reduces surface vaporisation and eliminates periodic surface structures. The measured electrical properties are still poor. Total-dose effects of gamma-ray irradiation on CMOS/ SIMOX devices. TERUKAZU OHNO, KATSUTOSHI [ZUMI, MASAKAZU SHIMAYAand NOSORU SHIONO. I E E E Circuits Devices Mag., 21 (November 1987). Radiation-hardened CMOS/SIMOX devices have been developed using a combination of vertical isolation structures obtained by SIMOX technology and newly developed lateral isolation structures. The n-channel MOSFET is vertically isolated by multilayers of highly oxygen-doped polysilicon and buried SiO2, and is laterally isolated by multilayers of thin sidewall SiO 2, sidewall polysilicon, and thick field SiO2. The p-channel MOSFET has the same vertical isolation structure as that of the n-channel MOSFET. However, it has no sidewall polysilicon layer but uses a thick field SiO 2 layer for lateral isolation. Highly oxygen-doped polysilicon and sidewall polysilicon layers act to shield radiation-