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Article: ALD Breaks Materials, Conformality Barriers.(Atomic layer deposition research)
- Article from:
- Semiconductor International
- Article date:
- October 1, 2001
- Author:
CopyrightCOPYRIGHT 2001 Reed Business Information. This material is published under license from the publisher through the Gale Group, Farmington Hills, Michigan. All inquiries regarding rights should be directed to the Gale Group. (Hide copyright information)
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Atomic layer deposition (ALD) is a thin-film deposition technique developed in Finland more than 20 years ago. [1] Like CVD, chemical reactants in ALD are introduced into the deposition chamber as gases (Fig. 1). In CVD, all reactants required for film growth are simultaneously exposed to a wafer surface, where they continuously deposit a thin film. CVD deposition rates can be surface-limited at lower temperatures, or mass-flow-limited at higher temperatures where deposition rates are relatively higher. In ALD, reactants are supplied in pulses, separated from each other in the flow stream by a purge gas. Each reactant pulse chemically reacts with the wafer surface. [2] It ...