Ge semiconductor devices for cryogenic power electronics - II

We have begun investigation and development of cryogenic semiconductor power devices (diodes, bipolar transistors and field-effect transistors) based on germanium. The motivation is NASA's interest in electronics that can operate down to deep cryogenic temperatures (as low as 30-40 K) for exploration of the outer planets and other Solar System bodies that present cold environments as well as for future space observatories. There are also potential applications related to cryogenic/superconducting motors and generators and power distribution and storage. We have characterized available Ge diodes and bipolar transistors at cryogenic temperatures and have begun examining MIS (metal-insulator-semiconductor) capacitors on Ge. Our investigations show that all these types of devices can operate from room temperature down to 20 K or lower.