A new method to form Au particle on silicon wafer

• Main Author: Yi, Qin.
• Other Authors: Tang Xiaohong
• Format: Final Year Project
• Language: English
• Published: 2013
• Subjects: DRNTU::Engineering
• Online Access: http://hdl.handle.net/10356/54206
• Institution: Nanyang Technological University

This project provides a research on a Reactive Ion Etch (RIE) based new method of synthesizing Au catalyst on the silicon substrate for semiconductor nanowires growths. The critical step in synthesizing semiconductor nanowires by VLS growth is the controlled preparation of the Au catalyst size on various substrates, which will determinate the diameter of nanowires. In this work, the reactive ion etching of gold films as thick as 600nm has been investigated. The etch chemistry utilized consists of a mixture of dichlorodifluoromethane (CCl2F2), tetrafluoromethane (CF4), and oxygen (O2). However, we need understand the relationship between Au particle size and RIE etch rate and etch rates were studied for various gas compositions, chamber pressures and power using a parallel plate reactive ion etcher. The etch process developed uses an eight inch oxidized silicon wafer, which serves as the substrate platter. The presence of this relatively large area of silicon dioxide during the etch process serves to prevent the accumulation of etching residues and polymer films atop the gold surface, which tend to inhibit the gold etch. A CCl2F2-based etch chemistry offers an advantage over other chlorine-based etches in that a standard fluorine reactive ion etching (RIE) system may be used. This eliminates the need for a more corrosive chlorine RIE system, reducing system complexity and avoiding the hazards of handling dangerous chlorine gases.