Cu-plated through-wafer vias for AlGaN∕GaN high electron mobility transistors on Si

Abstract

A robust method for creating Cu-plated through-wafer vias for AlGaN∕GaN high electron mobility transistors on Si is reported. The initial 70μm deep vias with diameters of 50μm are created by deep Si reactive ion etching, followed by pulsed Cu electroplating and mechanical polishing to planarize the metal. This is an attractive approach for increasing the effective thermal conductivity of the composite substrate for very high power device applications.