Fabrication of bipolar junction transistor on (001)-oriented diamond by utilizing phosphorus-doped n-type diamond base

Bipolar junction transistors (BJTs) with vertical p–n–p structure were fabricated on (001)-oriented diamond by utilizing phosphorus-doped diamond for the base n-type layer, and the electrical properties were examined, including the diffusion length of injected holes. The basic transistor action with stable current response from 100 nA to 50 μA was clearly observed at room temperature in both common-base and common-emitter configurations. Heavily phosphorus-doped diamond was introduced by the selective doping method under the base electrodes in order to reduce the series resistance, which is essential for realizing BJTs on (001).