GaN field-effect transistor, inverter device, and production processes therefor

摘要

A process of forming a high-resistance GaN crystal layer which is useful in producing a GaN FET. The high-resistance GaN crystal layer is formed by doping a GaN crystal with one or more acceptor-type impurities selected from the group consisting of C, Mg and Zn during epitaxial growth thereof. Specifically, during the epitaxial growth of the GaN crystal, the GaN crystal is doped with Mg or Zn in an atmosphere of hydrogen at a temperature of 600° C. or higher, or the GaN crystal is doped with Mg or Zn at a concentration of 1x1017 cm-3 or higher and then is doped with C at a concentration of 1x1018 cm-3 or higher. The GaN layer may be ion-implanted with an acceptor such as C, Mg or Zn or with a donor such as Si, to control the carrier density and thus the threshold value.