A 17.5-GHz 3-bit phase-shift receive MMIC-fabrication and test results

A high-yield, FET gate fabrication technology is described. The main advantage of this processing approach is that it permits fabrication of devices with gate lengths of less than 0.5 mu m using standard optical photolithography without recourse to deep UV or electron-beam lithography. The process is simple and easy to implement in a manufacturing environment. Exceptionally good gate-length control, typically 10% for a 0.4- mu m-long gate, is demonstrated. Yield of a 300- mu m-wide FET, designed for use in a gain block and in a switch, is found to be 89% on average. Data on wafer-to-wafer and on-wafer variations in device DC and RF parameters and equivalent circuit values are presented. Typical standard deviations are in the 5-10% range. This process technology has been used to fabricate a 17.5-GHz, 3-b phase-shift receive monolithic microwave integrated circuit (MMIC) of moderately high complexity. Statistics of RF data on 704 such devices, fabricated over a period of two years, are presented. It is shown that such MMICs can be fabricated with yields sufficient for prototype active phased-array antenna applications.<
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