Catalyst preparation for CMOS-compatible silicon nanowire synthesis

TL;DR

This paper presents a novel catalyst preparation method enabling CMOS-compatible silicon nanowire synthesis at lower temperatures, overcoming previous temperature and material compatibility limitations.

Contribution

The authors develop a chemical catalyst preparation technique that allows silicon nanowire growth at temperatures below 450°C using copper, challenging the belief that oxygen inhibits nanowire growth.

Findings

Catalyst can be prepared at 400°C via chemical oxidation.

Oxidized catalyst enables nanowire growth at CMOS-compatible temperatures.

Method addresses both temperature and material compatibility issues.

Abstract

Metallic contamination was key to the discovery of semiconductor nanowires, but today it stands in the way of their adoption by the semiconductor industry. This is because many of the metallic catalysts required for nanowire growth are not compatible with standard CMOS (complementary metal oxide semiconductor) fabrication processes. Nanowire synthesis with those metals which are CMOS compatible, such as aluminium and copper, necessitate temperatures higher than 450 C, which is the maximum temperature allowed in CMOS processing. Here, we demonstrate that the synthesis temperature of silicon nanowires using copper based catalysts is limited by catalyst preparation. We show that the appropriate catalyst can be produced by chemical means at temperatures as low as 400 C. This is achieved by oxidizing the catalyst precursor, contradicting the accepted wisdom that oxygen prevents metal-catalyzed nanowire growth. By simultaneously solving material compatibility and temperature issues, this catalyst synthesis could represent an important step towards real-world applications of semiconductor nanowires.