Flex-ALD Lanthanum Materials for High-k/Metal-Gate Applications

Lanthanum oxide films are deposited using Flex-ALD^™ solution-based precursor formulations via atomic layer deposition. A solid La precursor is dissolved in solvent blends and the solution precursor is delivered via direct liquid injection methods to a vaporizer that is connected to the ALD chamber. The fully vaporized solution precursor is then pulsed into the deposition chamber containing an in- situ quartz crystal microbalance (QCM). High-k bi-layers are formed by growing a La oxide ALD layer onto an HfO₂ coated surface of a silicon wafer sample in the same ALD chamber. Composition analysis showed carbon and other contaminants are below 1 atomic %.