Microwave Operation Of A Diamond Field-Effect Transistor

By Makoto Kasu, NTT Basic Research Laboratories

Abstract

Among semiconductors, diamond intrinsically possesses many superior physical properties suitable for high-frequency, high-power electronic devices and is thus called the "ultimate semiconductor". NTT Basic Research Laboratories (BRL) has developed a technology for growing high-quality diamond film, and, in collaboration with the University of Ulm, Germany, successfully fabricated diamond field-effect transistors (FETs) using the film. These diamond FETs exhibited the highest cut-off frequency reported for diamond and showed the first amplification operation in the millimeter-wave range. Diamond FETs will replace the vacuum tubes currently used in the high-frequency, high-power regime and will enable us to greatly increase the output power of communications satellites and broadcasting stations.