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Hot spot effects in hybrid circuits
1102
World Abstracts on Microelectronics and Reliability
forward bias. Moreover, the large breakdown voltage which is observed indicates that high peak-power handling capability should be possible.
Automated inspection of general shapes. C. M. KLEIN, JA. VEN'It;R,e~ and C. A. CHANG. Comput. Intl. Enyn9 15, 355 (1988). The demand to minimize the number of defects along with the increasing availability of computerized vision systems has made the on-line inspection of all production parts a feasible option in modern manufacturing systems. Vision systems enable noncontact, and thus, nondestructive measurements. An image of the production part is electronically obtained and stored in digital form in a computer. In
7. S E M I C O N D U C T O R
INTEGRATED
Dependence of activation energy on subband splitting and magnetic field in silicon inversion layers. DRAGANA POPOVlC, E. E. I=AN(; and P. J. STILES. Solid St. Commun. 68, 25 (1988). The dependence of the activation energy on the subband splitting and on the perpendicular magnetic field in silicon inversion layers at low carrier densities has been studied. The subband splitting was first varied by changing the substrate bias. After exhibiting an initial drop at the smaller values of the subband splitting, the activation energy saturates and even shows a slight increase with increasing reverse substrate bias at the lowest carrier densities. While this increase is attributed to the increased surface roughness scattering at higher values of the surface field, the initial behaviour can be explained by the existence of the very long band tails associated with the primed subbands. Our magnetic field measurements were conducted in a weak-field limit. We have found an increase of the activation energy with the magnetic tield, which proceeds in a nonlinear fashion and can not be explained inerely by the change of the subband splitting in a magnetic field.
Deternfination of the mobility profile in silicon-on-sapphire material using the "fat" FET principle. A SODERUARG, M. ROSHY(;, H. NORDE and P. A. TOVE. Solid-St. Electron. 31, 1583 (1988). Using a field effect transistor (FET) structure with a Schottky gate, the mobility profile in a silicon layer is calculated from capacitance and conductance measurements. The measurements require ordinary laboratory instruments only. A short theory is presented, followed by experimental values for silicon on sapphire (SOS) material. The results show a sharp decrease in mobility at the defect rich layer close to the sapphire and close to the silicide gate junction. A m a x i m u m mobility of 490cmZ/Vs for electrons and 190cm2/Vs for holes was obtained for a position roughly in the middle of the silicon layer.
Integer monolayer metallic superlattices. JOHN L. MAKOUS and CHAI
most cases, the image is then processed to identify the local edges of the object. At a higher image processing level, information on local edges is used to obtain the boundaries of the object. Measurements on the computationally obtained boundary can then be performed mathematically, allowing tests to verify the shape and dimensions of the production part. It is the purpose of this paper to investigate and present methods for the determination of shapes and the use of this information for on-line quality inspection.
Testing boards with the VXIbus. STEPHEN E. SCHEIBER. "lest Measuremt Wld, 38 (August 1988). Developing VXlbusbased board-test systems will be very much like developing IEEE488-based systems only better.
CIRCUITS,
DEVICES
AND
MATERIALS
establishes the conditions under which a set of Boltzmannlike carrier density equations commonly used in device analysis are valid. The relationship between ni~ and the change in bandgap AEg is clarified. The results pertain directly to the analysis of highly doped devices and heterostructures.
Avoiding low temperature thermal donors in CMOS. E. GO~OON WRIGHT. Semiconductor int., 134 (September 1988). A simple model can help you understand and avoid the temperature- and oxygen-dependent effects of thermal donors.
Charge trapping and detrapping phenomena in thin oxide-nitride oxide stacked films. S. K. LEE, J. H. CHEN, Y. H. KL', D.L. KWONG, B.Y. NGUYEN and K. W, TENG. Solid-St. Electron. 31, 1501 (1988). A reversible electron trapping phenomenon in thin oxide/nitride/oxide (ONO) films with respect to stress current and field near the tunneling region is demonstrated for the first lime. Trapped electrons can be detrapped by applying a low field or low current stressing under negative gate bias. A very effective electron detrapping process in the thin nitride layer is proposed to explain these unusual trapping behaviours of thin O N O films. The effects of processing chemistry of silicon nitride deposition on the electrical characteristics of thin O N O capacitors and their stability are also discussed.
Influence of silicon sapphire interface defects on SOS M E S F E T behaviour. J.O. NYLANDER,U. MAGNUSSON, M. ROSLING and P.A. TovE. Solid-St. Electron. 31, 1493 (1988). Silicon M E S F E T s in silicon-on-sapphire SOS technology were studied and a comparison was made between simulated and measured I V characteristics of normally-off transistors. The comparisons have shown that the effective conductingchannel depth is only 401~, of the actual Si film thickness. A novel simulation approach to compensate for the lack of free carriers close to the sapphire interface is described. Results from measured transistors is presented together with simulated behaviour, and also a comparison between simulated and experimental complementary M E S F E T (CMES) inverter behaviour is done. The influence of interface defects on subthreshold current is also discussed.
Electron mobility in ln0.s3Ga0.4~As. ANTON1N ZOUL. T E S L A Electron., 3 4, 56 (1986). The paper provides an analysis of the temperature dependence of electron mobility in In0.53Ga0.47As/InP epitaxial layers. A computer has been used to find optimum fits of the measured dependences with theoretical curves in the least-squares sense and to evaluate the concentration of dopants as well as the frequency of structural defects. It is shown that low concentration and small size of the space charge regions play an essential role in attaining high mobility in these layers at room temperature.
World Abstracts on Microelectronics and Reliability
forward bias. Moreover, the large breakdown voltage which is observed indicates that high peak-power handling capability should be possible.
Automated inspection of general shapes. C. M. KLEIN, JA. VEN'It;R,e~ and C. A. CHANG. Comput. Intl. Enyn9 15, 355 (1988). The demand to minimize the number of defects along with the increasing availability of computerized vision systems has made the on-line inspection of all production parts a feasible option in modern manufacturing systems. Vision systems enable noncontact, and thus, nondestructive measurements. An image of the production part is electronically obtained and stored in digital form in a computer. In
7. S E M I C O N D U C T O R
INTEGRATED
Dependence of activation energy on subband splitting and magnetic field in silicon inversion layers. DRAGANA POPOVlC, E. E. I=AN(; and P. J. STILES. Solid St. Commun. 68, 25 (1988). The dependence of the activation energy on the subband splitting and on the perpendicular magnetic field in silicon inversion layers at low carrier densities has been studied. The subband splitting was first varied by changing the substrate bias. After exhibiting an initial drop at the smaller values of the subband splitting, the activation energy saturates and even shows a slight increase with increasing reverse substrate bias at the lowest carrier densities. While this increase is attributed to the increased surface roughness scattering at higher values of the surface field, the initial behaviour can be explained by the existence of the very long band tails associated with the primed subbands. Our magnetic field measurements were conducted in a weak-field limit. We have found an increase of the activation energy with the magnetic tield, which proceeds in a nonlinear fashion and can not be explained inerely by the change of the subband splitting in a magnetic field.
Deternfination of the mobility profile in silicon-on-sapphire material using the "fat" FET principle. A SODERUARG, M. ROSHY(;, H. NORDE and P. A. TOVE. Solid-St. Electron. 31, 1583 (1988). Using a field effect transistor (FET) structure with a Schottky gate, the mobility profile in a silicon layer is calculated from capacitance and conductance measurements. The measurements require ordinary laboratory instruments only. A short theory is presented, followed by experimental values for silicon on sapphire (SOS) material. The results show a sharp decrease in mobility at the defect rich layer close to the sapphire and close to the silicide gate junction. A m a x i m u m mobility of 490cmZ/Vs for electrons and 190cm2/Vs for holes was obtained for a position roughly in the middle of the silicon layer.
Integer monolayer metallic superlattices. JOHN L. MAKOUS and CHAI
most cases, the image is then processed to identify the local edges of the object. At a higher image processing level, information on local edges is used to obtain the boundaries of the object. Measurements on the computationally obtained boundary can then be performed mathematically, allowing tests to verify the shape and dimensions of the production part. It is the purpose of this paper to investigate and present methods for the determination of shapes and the use of this information for on-line quality inspection.
Testing boards with the VXIbus. STEPHEN E. SCHEIBER. "lest Measuremt Wld, 38 (August 1988). Developing VXlbusbased board-test systems will be very much like developing IEEE488-based systems only better.
CIRCUITS,
DEVICES
AND
MATERIALS
establishes the conditions under which a set of Boltzmannlike carrier density equations commonly used in device analysis are valid. The relationship between ni~ and the change in bandgap AEg is clarified. The results pertain directly to the analysis of highly doped devices and heterostructures.
Avoiding low temperature thermal donors in CMOS. E. GO~OON WRIGHT. Semiconductor int., 134 (September 1988). A simple model can help you understand and avoid the temperature- and oxygen-dependent effects of thermal donors.
Charge trapping and detrapping phenomena in thin oxide-nitride oxide stacked films. S. K. LEE, J. H. CHEN, Y. H. KL', D.L. KWONG, B.Y. NGUYEN and K. W, TENG. Solid-St. Electron. 31, 1501 (1988). A reversible electron trapping phenomenon in thin oxide/nitride/oxide (ONO) films with respect to stress current and field near the tunneling region is demonstrated for the first lime. Trapped electrons can be detrapped by applying a low field or low current stressing under negative gate bias. A very effective electron detrapping process in the thin nitride layer is proposed to explain these unusual trapping behaviours of thin O N O films. The effects of processing chemistry of silicon nitride deposition on the electrical characteristics of thin O N O capacitors and their stability are also discussed.
Influence of silicon sapphire interface defects on SOS M E S F E T behaviour. J.O. NYLANDER,U. MAGNUSSON, M. ROSLING and P.A. TovE. Solid-St. Electron. 31, 1493 (1988). Silicon M E S F E T s in silicon-on-sapphire SOS technology were studied and a comparison was made between simulated and measured I V characteristics of normally-off transistors. The comparisons have shown that the effective conductingchannel depth is only 401~, of the actual Si film thickness. A novel simulation approach to compensate for the lack of free carriers close to the sapphire interface is described. Results from measured transistors is presented together with simulated behaviour, and also a comparison between simulated and experimental complementary M E S F E T (CMES) inverter behaviour is done. The influence of interface defects on subthreshold current is also discussed.
Electron mobility in ln0.s3Ga0.4~As. ANTON1N ZOUL. T E S L A Electron., 3 4, 56 (1986). The paper provides an analysis of the temperature dependence of electron mobility in In0.53Ga0.47As/InP epitaxial layers. A computer has been used to find optimum fits of the measured dependences with theoretical curves in the least-squares sense and to evaluate the concentration of dopants as well as the frequency of structural defects. It is shown that low concentration and small size of the space charge regions play an essential role in attaining high mobility in these layers at room temperature.