Atomic layer deposition of HfO₂ using HF etched thermal and RTP SiO₂ as interfacial layers

Atomic Layer Deposition (ALD) of HfO₂ on Si substrates requires an interfacial oxide layer, which should be full of hydroxyl groups (-OH groups) or hydrophilic. Chemical oxide grown by SC1 solution is widely used as an ideal interfacial layer. It was reported that thermal SiO₂ and RTP SiO₂ are not good as interfacial layers because they are lack of OH groups. In this research, we found that diluted HF etching of thermal SiO₂ and RTP SiO₂ could create hydrophilic surfaces, which could be used as interfacial layers for ALD of HfO₂. The electrical properties of the HfO₂ grown on etched thermal and RTP SiO₂ is not significantly degraded comparing to the HfO₂ grown on chemical oxide.