Emitter-down, Schottky collector HJBT for very fast, high-density logic applications

A novel form of direct-coupled logic is reported, incorporating an 'emitter-down' heterojunction bipolar transistor with a Schottky collector as the switching element and a pinched-off MESFET as the load. This technology has the potential for very high packaging density together with high speed because the Schottky cannot store charge. Results are presented for the bipolar device, and problems associated with 'inverted' operation are discussed. >