PROCESS-INDUCED DEFECTS IN MANUFACTURE OF GAAS MONOLITHIC MICROWAVE INTEGRATED-CIRCUITS

Semi-insulating liquid-incapsulated Czochralski GaAs wafers are genera lly used as substrates for the fabrication of monolithic microwave int egrated circuits. In the fabrication process, the wafer is subjected t o temperature cycling during the various stages of processing, namely post-ion implantation annealing, plasma deposition of dielectrics, dep osition of ohmic contacts and its alloying etc., which can induce stra ins and dislocations in the host wafer. In this paper, a study using t he photoluminescence (PL) technique has been carried out to understand the behaviour of different peaks under different processing condition s. Owing to temperature cycling and plasma deposition, it affects the PL peaks which is indicative of different types of defect introduced d uring processing.