Atomic layer deposition of high quality HfO₂ using in-situ formed hydrophilic oxide as an interfacial layer

High-quality HfO₂ cannot be grown directly on Si substrate using atomic layer deposition (ALD), and an interfacial oxide layer is needed. Traditionally, interfacial oxide layer is formed either in SC1 solution (2 NH₄OH: 4 H₂O₂: 200 H₂O) or by ozonated water spraying. A highly hydrophilic SiO₂ interfacial layer was in-situ formed in the ALD chamber using 1 cycle of ozone and water. The HfO₂ deposited on this interfacial layer showed great growth linearity. The gate leakage current is comparable to that formed using chemical oxide as the interfacial layer. The capacitance-voltage (C-V) curves have negligible frequency dispersion and hysteresis, which suggest high quality in both the interface and electrical properties. The in-situ formation of hydrophilic interfacial layer have advantages over the traditional interfacial layer. This might be useful for formation of interfacial layer on sophisticated 3-D MOS structures such as FinFETs and nanowire FETs. In addition, the chemical oxidation step can be eliminated from the integrated circuits manufacturing processes, which is economically beneficial to the industry.