Device testing for the development of an HBT IC process

A description is presented of the DC and microwave testing required for the development of an HBT (heterojunction bipolar transistor) integrated circuit process. Process control monitoring structures have been designed to allow device testing at several stages in processing. Wafer mapping of device parameters shows patterns which can help one to understand the process and improve yield. A database has been set up of device parameters. Examining the relation between various transistor parameters has led to experiments to understand the device current gain and has shown some unexpected results.<
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