Understanding the Mechanism of Electronic Defects Suppression Enabled by Non-Idealities in Atomic Layer Deposition

Silicon germanium (SiGe) is a multi-functional material considered for quantum computing, neuromorphic devices and CMOS transistors. However, implementation of SiGe in nano-scale electronic devices necessitates suppression of surface states dominating on electronic properties. The absence of a stable and passive surface oxide for SiGe results formation of charge traps at the SiGe - oxide interface induced by GeOx. In an ideal ALD process in which oxide is grown layer-by-layer, the GeOx formation should be prevented with selective surface oxidation (i.e. formation of an SiOx interface) by controlling oxidant dose in first few ALD cycles of the oxide deposition on SiGe. However, in a real ALD process, the interface evolves during entire ALD oxide deposition due to diffusion of reactant species through the gate oxide. In this work, this diffusion process in non-ideal ALD is investigated and exploited: the diffusion through the oxide during ALD is utilized to passivate the interfacial defects by employing ozo...