Controlled composition using plasma-enhanced atomic layer deposition
AssigneeASM America, Inc.
InventorKai-Erik Elers
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Abstract
Metallic-compound films are formed by plasma-enhanced atomic layer deposition (PEALD). According to preferred methods, film or thin film composition is controlled by selecting plasma parameters to tune the oxidation state of a metal (or plurality of metals) in the film. In some embodiments, plasma parameters are selected to achieve metal-rich metallic-compound films. The metallic-compound films can be components of gate stacks, such as gate electrodes. Plasma parameters can be selected to achieve a gate stack with a predetermined work function.
Claims32
A method of depositing a metallic-compound film in a plasma-enhanced atomic layer deposition (PEALD) process, comprising:
- alternately and sequentially contacting a substrate in a reaction space with spatially and temporally separated vapor phase pulses of at least three different reactants, the at least three different reactants comprising:
- a metal source chemical;
- a plasma-excited species;
- and
- a source chemical of a non-metal species desired in the metallic-compound film,
- wherein plasma parameters for generating the plasma-excited species are selected to reduce the oxidation state of the metal in the metallic-compound film relative to its oxidation state in the metal source chemical and achieve the metallic-compound film with a predetermined composition.
An atomic layer deposition (ALD) process for growing a thin metallic-compound film, comprising alternately and sequentially contacting a substrate in a reaction space with spatially and temporally separated vapor phase pulses of:
- a precursor of a metal that forms no more than about one monolayer of adsorbed species on an exposed surface of the substrate, the adsorbed species comprising at least one type of metal;
- a plasma-excited species reacting with the metal;
- and
- a source chemical of a species to be incorporated in the thin metallic-compound film,
- wherein plasma parameters for generating the plasma-excited species are selected such that the stoichiometric ratio between the metal and the species in the thin metallic-compound film is greater than one.
Dependencies are inferred from the claim text.