P A P E R    T I T L E
Suppression of Anomalous Electrochemical Etching by Reducing Dissolved Oxygen in Deionized Water for HEMT Process

A U T H O R  /  C R E D I T S
M. Tsunotani, T. Ohshima, M. Sato, R. Shigemasa and T. Kimura
Semiconductor Technology Laboratory, Oki Electric Industry Co., Ltd.
550-5 Higashiasakawa-cho, Hachioji, Tokyo 193-8550, Japan
Phone: +81-426-6764, Fax: +81-426-6770, E-mail: tunotani@hlabs.oki.co.jp

A B S T R A C T
In the InGaAs/AlGaAs HEMT fabrication process, we found an anomalous etching phenomena of the recess region during rinse process in deionized water. The anomalous etching occurred at the boundary between the n-type channel region and the isolation region, and at the gate recess region around the Al/Ti gate. This can be understood as an electrochemical etching effect caused by metal electrodes(cathode) and GaAs surface in the recess region(anode). In this paper, we describe such a phenomenon then propose a method to suppress that.