Low cost X-band power amplifier MMIC fabricated on a 0.25 /spl mu/m GaAs pHEMT process

A family of X-Band MMIC power amplifiers using a low cost GaAs pHEMT process is reported. The stepper based volume 0.5 micron and 0.25 micron GaAs pHEMT processes utilize 4 inter-level metallisation and four dielectric layers for high frequency performance whilst maintaining the economies of scale of 150 mm (6") diameter substrates. The fabricated GaAs X-Band PA MMICs exhibit 5 W to 10 W RF output power under pulsed conditions; 16 dB of power gain and power added efficiencies approaching 40%. Excellent repeatability and high yields over a number of wafers have been demonstrated. The design and GaAs process approach taken here with DUV stepper and 150 mm wafer diameter will lead to a significant cost reduction for high performance power amplifier MMICs up to 30 GHz.

1. INTRODUCTION

There is a continuous drive to reduce the cost and weight and improve the performance of T/R modules for airborne radars. One of the key components in the modules is the high power amplifier, which may need to deliver power output in excess of 10W. A Microwave Monolithic Integrated Circuit (MMIC) approach is particularly well suited to this application because of the small size and weight and the ability to manufacture with a repeatable performance in high volumes.