Assessment of Japanese Research and Development on High Temperature Electronics

Background

Solid state devices are being used increasingly to provide the means for computerized control and sensing in severe environments. Solid state sensors are particularly useful for this purpose, since they can be fully integrated with all of the necessary electronics incorporated on a single chip. New generation sensors also require integrated circuitry for controlling bus interfaces and performing self-tests and auto-calibration. The ability of such on-chip electronics to survive severe operating conditions is becoming increasingly important as sensors are applied in machinery on the factory floor and in automobile and jet engines, deep-well instruments, chemical processing plants, spacecraft, and many other remote, hot, high radiation, or electrically noisy environments.

In addition, there is a need to minimize the requirements for cooling in electronic packaging systems. A very significant fraction of the total mass of some military aircraft is in refrigeration for onboard electronics. Therefore substantial improvements in both performance and cost of complex systems that incorporate electronic controls and sensors could be obtained if their circuitry operated reliably at elevated temperatures.

Silicon-based semiconductors have traditionally been specified to operate only up to 125^oC. Applications for solid state sensors, signal processing in-situ, and control circuitry for automotive, aircraft, space, and other hostile and hot environments require circuitry that can operate at higher temperatures (e.g., 200^oC and up) and in environments where temperature may vary widely. Materials that have been investigated for design of semiconductor devices that can withstand these conditions include bulk CMOS (<200^oC), EPI CMOS (<250^oC ) SOI CMOS (<300^oC ), and SiC (<650^oC). The emphasis in this study will be on silicon carbide and gallium nitride.

Japan has an advanced electronics industry and has developed the capability to produce ultra-pure SiC. In 1993, Toshiba Ceramics announced it had built a pilot plant to mass produce semiconductor-grade SiC in production line fashion. Moving the production of ultrapure SiC from batch mode, which is still employed by U.S. firms, to planned mass production as shown in Japan, represents a very significant advancement in production engineering process.Japanese labs have also reported considerable progress in gallium nitride areas.

Purpose

This study will review the current status of Japanese research, development, and applications in silicon carbide and gallium nitride for devices to be used in severe, especially high temperature, environments. The objectives of the study will be to evaluate the competitive status of Japanese efforts in this field, assess current collaborative activities, and identify and discuss key Japanese technological developments in the field.

Technologies to be Covered

The following topics and issues will be addressed by the sponsors and panelists in the study.

• silicon carbide technology
• gallium nitride technology
• bulk material fabrication
• epitaxial growth
• oxide growth
• etching techniques
• device fabrication
• electronic packaging and interconnections for high temperature applications
• high temperature transistors and other active devices
• high temperature sensors and capacitors

Panelists

Vladimir Dmitriev, Chair
TDI, Inc. and Howard University

T. Paul Chow
Rensselaer Polytechnic Institute

R. Chris Clarke
Northrop Grumman

Steven P. DenBaars
University of California, Santa Barbara

Michael S. Shur
Rensselaer Polytechnic Institute

Peter Stipan
Rockwell International