A novel fabrication process of surface via-holes for GaAs power FETs

Abstract

A simple new fabrication process of via-holes has been developed for GaAs power FETs. This process features deep trench etching from the wafer surface followed by refilling the trench by conformal electro-plating. The Surface Via-Hole (SVH) is engraved by extremely high rate ECR etching. We obtained the etching rate of over 4 /spl mu/m/min with a completely anisotropic smooth profile. The conformal metal deposition around the trench is achieved by pulse-modulated electro-plating. The GaAs power FET with SVH showed better linearity than the conventional wire-bonded one. The present SVH process is applicable to almost all the GaAs FETs or MMICs with very small area consumption and suitable for the high volume production.