Manufacturing AlGaAs/GaAs HBTs on 100 mm wafers

The authors report the first implementation of HBT technology on 100 mm OMVPE-grown epitaxial wafers. The electronic characteristics of large area HBT devices with an emitter size of 67/spl times/67 /spl mu/m/sup 2/ are used to measure the uniformity of the epitaxial material. The variations of current gain and V/sub be/ turn-on voltage for such devices are less than 3% and 1%, respectively, across a wafer. This indicates that the characteristic uniformity of epitaxial films grown on 100 mm wafers is comparable with films grown on three-inch wafers. Process induced variation in the device characteristics is measured on small area devices with an emitter size of 1.4/spl times/3 /spl mu/m/sup 2/. The across wafer variations of current gain and V/sub be/ turn-on voltage for these devices are less than 10% and 1%. Circuit yield sufficient for production ramp-up has been demonstrated for gain blocks, prescalers, 14-bit digital-to-analog converters and 8-bit analog-to-digital converters. The success over this array of products demonstrates that the OMVPE-grown 100 mm epitaxial wafers and the HBT fabrication process developed are well suited for a production environment.<
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