Atomic Layer Deposition: An Overview

Atomic layer deposition (ALD) which has emerged as an important technique for depositing thin films for a variety of applications has been reported. The necessity for continuous and pinhole-free films in semiconductor devices has driven the advancement of ALD. ALD is able to meet the needs for atomic layer control and conformal deposition using sequential, self-limiting surface reactions. The ALD of Al2O3 has developed as a model ALD system. ALD processing is also extendible to very large substrates and to parallel processing of multiple substrates. ALD is a gas phase method based on sequential, selflimiting surface reactions. ALD can deposit very conformal and ultrathin films on substrates with very high aspect ratios. ALD on high aspect ratio structures was then considered including an examination of the times required for conformal growth on high aspect ratio structures. The number of applications for ALD also continues to grow outside of the semiconductor arena.