MONOLITHICALLY INTEGRATED HBT MESFET CIRCUIT

The first circuit demonstrated using monolithically integrated GaAlAa/ GaAs heterojunction bipolar transistors (HBTs) and metal-semiconductor field effect transistors (MESFETs) is described. The fabrication tech nology is a natural extension to our baseline HBT technology. The plan arity of the device fabrication process allows the MESFETs and HBT, to be closely spaced. The circuit, a CML-DCFL-CML convertor, is an impor tant building block for the future integration of HBT and MESFET circu itry. This circuit consists of HBTs, and enhancement (E) and depletion (D) mode MESFETs. The circuit operated properly at 1 GHz.