Scaling the silicon bipolar transistor for sub-100-ps ECL circuit operation at liquid nitrogen temperature

A two-dimensional device simulator was used to examine the various profile design strategies for silicon bipolar transistors operating at liquid-nitrogen temperatures. Special emphasis was placed on the scaling tradeoffs of these design approaches. It is concluded that a relaxed scaling technique based on the maintenance of constant base Gummel number with a slight decrease in emitter doping level probably offers the best overall low-temperature design strategy for scaled double-polysilicon devices. To verify these calculations, devices with 0.8- mu m lithography were fabricated using this design scheme. Transistors were found to be reasonably ideal at low temperatures and had adequate current gain for most digital applications. Unloaded ECL ring oscillators operated at sub-100-ps speeds at liquid-nitrogen temperatures. Simulations based on measured data indicate that sub-150-ps loaded ECL delays are achievable at about 4-mW power at 87 K if the circuit logic swing is reduced to 300 mV. These data suggest that conventionally designed silicon bipolar transistors are attractive candidates for very-high-performance applications in the low-temperature environment. >

[1]  W. Kauffman,et al.  The temperature dependence of ideal gain in double diffused silicon transistors , 1968 .

[2]  D. Tang,et al.  Bipolar circuit scaling , 1979, 1979 IEEE International Solid-State Circuits Conference. Digest of Technical Papers.

[3]  D. Tang.  Heavy doping effects in p-n-p bipolar transistors , 1980, IEEE Transactions on Electron Devices.

[4]  W. Dumke.  The effect of base doping on the performance of Si bipolar transistors at low temperatures , 1981, IEEE Transactions on Electron Devices.

[5]  E. M. Buturla,et al.  Finite-element analysis of semiconductor devices: the FIELDAY program , 1981 .

[6]  R. M. Swanson,et al.  Simultaneous measurement of hole lifetime, hole mobility and bandgap narrowing in heavily doped n-type silicon , 1985, 1985 International Electron Devices Meeting.

[7]  C. C. Ng,et al.  A thermionic-diffusion model of polysilicon emitter , 1986, 1986 International Electron Devices Meeting.

[8]  R. M. Swanson,et al.  Measurement of electron lifetime, electron mobility and band-gap narrowing in heavily doped p-type silicon , 1986, 1986 International Electron Devices Meeting.

[9]  D. Harame,et al.  High performance operation of silicon bipolar transistors at liquid nitrogen temperature , 1987, 1987 International Electron Devices Meeting.

[10]  J. Woo,et al.  Non-ideal base current in bipolar transistors at low temperatures , 1987, IEEE Transactions on Electron Devices.

[11]  J. Woo,et al.  Optimization of bipolar transistors for low temperature operation , 1987, 1987 International Electron Devices Meeting.

[12]  Denny D. Tang,et al.  Junction degradation in bipolar transistors and the reliability imposed constraints to scaling and design , 1988 .

[13]  Huanjing Chen,et al.  Switching characteristics of poly bipolar circuits at liquid nitrogen temperature , 1988, Proceedings of the 1988 Bipolar Circuits and Technology Meeting,.

[14]  K. Jenkins,et al.  On the low-temperature static and dynamic properties of high-performance silicon bipolar transistors , 1989 .

[15]  D. Tang,et al.  Injection-induced bandgap narrowing and its effects on the low-temperature operation of silicon bipolar transistors , 1989 .

[16]  Keith A. Jenkins,et al.  Low-temperature operation of silicon bipolar ECL circuits , 1989, IEEE International Solid-State Circuits Conference, 1989 ISSCC. Digest of Technical Papers.

[17]  D. Tang,et al.  The effects of injection induced bandgap narrowing on bipolar transistors operating at low temperatures , 1989, Proceedings of the Workshop on Low Temperature Semiconductor Electronics,.

[18]  D. Harame,et al.  Epitaxial-base transistors with ultrahigh vacuum chemical vapor deposition (UHV/CVD) epitaxy: enhanced profile control for greater flexibility in device design , 1989, IEEE Electron Device Letters.