Cryogenic Operation of Silicon Power Devices

The advent of low temperature superconductors in the early 1960's converted what had been a laboratory curiosity with very limited possibilities to a prac tical means of fabricating electrical components and devices with lossless con ductors. Using liquid helium as a coolant, the successful construction and operation of high field strength magnet systems, alternators, motors and trans mission lines was announced. These developments ushered in the era of what may be termed cryogenic power engineering and a decade later successful oper ating systems could be found such as the 5 T saddle magnet designed and built in the United States by the Argonne National Laboratory and installed on an experimental power generating facility at the High Temperature Institute in Moscow, Russia. The field of digital computers provided an incentive of a quite different kind to operate at cryogenic temperatures. In this case, the objective was to ob tain higher switching speeds than are possible at ambient temperatures with the critical issue being the operating characteristics of semiconductor switches under cryogenic conditions. By 1980, cryogenic electronics was established as another branch of electric engineering.

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This is the first comprehensive resource of power device electrical characteristics in a cryogenic environment. Using theoretical and experimental knowledge from the literature, temperature dependence of fundamental silicon material parameters like intrinsic carrier concentration, carrier mobilities, lifetimes and bandgap narrowing was identified. The temperature dependent model of avalanche breakdown was developed using experimental data on numerous devices. A wide range of power devices, each with its own unique features, was chosen for theoretical and experimental analysis. Using these analyses, Schottky diodes, power MOSFETs, power BJTs, and power JFETs were optimized in the 300-77K temperature range. Cryogenic Operation of Silicon Power Devices presents the different characteristics of power devices operated below -55°C (220K). It provides data and physics based models for power devices operated at temperatures down to 77K for the first time within a single source. All commercially available devices have been included to provide comprehensive coverage. Also, a fundamental analysis of devices identifies the suitability of various devices to applications requiring cryogenic operations. A quantitative analysis of the relative strengths and weaknesses of these devices is also presented.

Contenu

1. Introduction.- 1.1 Advent of Power Cryoelectronics.- 1.2 Cryogenic Power Applications.- 1.3 Advantages of using semiconductor devices at low temperatures.- 1.4 Inferences and Objectives.- 2. Temperature Dependence of Silicon Properties.- 2.1 Semiconductor statistics and carrier Freezeout.- 2.2 Energy bandgap of Silicon.- 2.3 Intrinsic Carrier Concentration.- 2.4 Carrier Mobility.- 2.5 Carrier Lifetime.- 2.6 Breakdown Phenomenon.- 3. Schottky Barrier Diodes.- 3.1 Device Operation.- 3.2 Experimental Results.- 3.3 Optimization of Schottky Barrier Diodes for low temperature operation.- 3.4 Conclusions.- 4. P-I-N Diode.- 4.1 Basic Structure.- 4.2 Experimental Results.- 4.3 Analytical Modeling.- 4.4 Conclusions.- 5. Power Bipolar Transistors.- 5.1 Basic Operation.- 5.2 Experimental Results.- 5.3 Emitter Current Crowding.- 5.4 Transistor Optimization.- 5.5 Conclusions.- 6. Power Mosfets.- 6.1 Device Operation.- 6.2 Carrier freezeout in silicon.- 6.3 Experimental Results.- 6.4 Discussion.- 6.5 Conclusion.- 7. Insulated Gate Bipolar Transistors.- 7.1 Device operation.- 7.2 Experimental results.- 7.3 Conclusion.- 8. Power Junction Field Effect Transistors.- 8.1 Basic Operation.- 8.2 Forward Blocking.- 8.3 Forward Conduction.- 8.4 Conclusions.- 9. Asymmetric Field Controlled Thyristors.- 9.1 Basic Operation.- 9.2 Static Characteristics.- 9.3 Switching Characteristics.- 9.4 Trade-Off curve and Conclusions.- 10. Thyristors.- 10.1 Basic Operation.- 10.2 Static Characteristics.- 10.3 Switching Characteristics.- 10.4 Conclusions.- 11. Synopsis.- 11.1 Design considerations for power devices at 77K.- 11.2 Performance of power devices at 77K.- 11.3 Power devices for cryogenic applications.- References.