Inductively Coupled Plasma Etching of Silicon Using Solid Iodine as an Etching Gas Source

We investigated the Si dry etching process by inductively coupled plasma (ICP) using solid I 2 as an etching gas source. A vertical etching profile and a smooth etched surface, which satisfy the requirements for optical device fabrication, were obtained at a relatively higher substrate temperature. The etching rate of Si was approximately 90 nm/min at 1 Pa and at an ICP/bias RF power of 300/100 W. The I 2 plasma etching technique is a very simple C-, CF-, and H-free process. In addition, we believe that this proposed process is useful for fabricating Si-based optical devices, such as photonic crystals, narrow optical waveguides, and micro-electro-mechanical systems (MEMS).