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 I2 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 I2 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).