P A P E R    T I T L E
A Product Engineering Exercise in 6-Sigma Manufacturability: Redesign of a PHEMT Wide-Band LNA

A U T H O R  /  C R E D I T S
Marcus King, Porter Hull*, Mark Tanner*, John Beall, Scott Walthers, Keith Salzman, and Matthew Parker*
TriQuint Semiconductor, P.O. Box 833938, Richardson, TX 75083
*Raytheon Systems, P.O. Box 660246, M/S 255 Dallas, TX 75266

The ability to design any MMIC to meet given performance specifications requires accurate knowledge of the nominal equivalent circuit parameters (ECPs) used to describe the frequency response of the FET building block, and a knowledge of the long-term statistical variation of the ECPs at the bias point of the particular MMIC. Normal SPC control procedures in semiconductor manufacturing accumulate long-term data on DC and RF parameters. The basic DC measurements of the FET building block are relatively easy to maintain, monitor, and characterize for long-term statistical variation. However, resource limitations prevent similar accumulation of RF data for the many different bias conditions used in various MMICs. Instead, long-term RF data are usually accumulated at a fixed bias using FET building blocks included on each wafer.

This paper will describe the application of an alternative scheme to the redesign of a pHEMT wideband distributed LNA, originally designed using a model generated from a small set of FET building blocks. Performance before and after the redesign will be compared. Also, a straightforward scheme for maintaining a long term database of RF performance at standard conditions will be described.