InP hot electron transistors with a buried metal gate

To apply the ballistic nature of hot electrons, an InP hot electron transistor with a buried metal (BM-HET) is reported. In this device, carriers are extracted from the emitter by an attractive potential originating from an embedded metal grating, and they propagate through intrinsic semiconductor material only. A simple estimation shows a high cutoff frequency and low output conductance. The estimated highest cutoff frequency is approximately 1 THz. Fabricated devices show that the collector current increased with the gate bias. After extraction of the leakage cur-rent, a clear saturation of the collector current in common-emitter characteristics was confirmed and the possibility of BM-HET as a candidate for high-speed electron devices was demonstrated