Abstract
Dry etching process used for the fabrication of power devices requires high level process technology and highly advanced systems.What is especially difficult in the dry etching process for power device fabrication is GaN/AlGaN recess etching for gate formation.2DEG must be eliminated to realize normally-off type powerdevices,and one of the solutions is to make AlGaN layer very thin. In order to etch away 20nm from AlGaN layer that is initially 25nm thick, and to realize stable device properties such as Vg-Id, it is extremely important to precisely control the thickness of 25nm.Our challenges of recess etching include(i) low etch rate process,(ii) end point detection,(iii) bottom smoothness,and (iv) device damage.We developed a new etching process to solve these challenges and new technology to optically monitor remaining layer thickness during dryetching
