InGaAs(001) and SiGe(001)/(110) Surface Passivation by Self-Limiting Deposition of Silicon Containing Control Layers
- Author(s): Edmonds, Mary Ellen;
- Advisor(s): Kummel, Andrew;
- et al.
Metal oxide semiconductor field effect transistors (MOSFETs) are transitioning away from exclusive use of silicon and germanium into the employment of compound semiconductors such as SiGe and InGaAs to further increase transistor performance. A broader range of channel materials with higher electron or hole mobilities may be employed if a universal control interfacial layer, which bonds more ideally to high-k gate oxide materials, could be ALD or self-limiting CVD deposited on many different materials and crystallographic faces. Silicon bonds strongly to all crystallographic faces of InGa1-xAs, InxGa1-xSb, InxGa1-xN, SiGe, and Ge enabling transfer of substrate dangling bonds to silicon, which may then be passivated with atomic hydrogen, or functionalized with an oxidant such as HOOH(g) in order to create an Si-OH layer, or a nitriding agent such as N2H4(g) in order to create an SiOxNy diffusion barrier and surface protection layer. This dissertation focuses on depositing saturated Si-Hx, and Si-OH thin films via three separate self-limiting CVD processes on InGaAs(001)-(2x4), and depositing a SiOxNy thin film on Si0.5Ge0.5(110), Si0.5Ge0.5(001), and Si0.7Ge0.3(001) surfaces via an ALD process. XPS in combination with STS/STM were employed to characterize the electrical and surface properties of these silicon containing thin films on InGaAs(001)-(2x4) and SixGe1-x(110)/(001) surfaces. MOSCAP device fabrication was performed on n-type InGaAs(001), Si0.5Ge0.5(001), and Si0.7Ge0.3(001) substrates with and without the insertion of these silicon containing interfacial control layers deposited by novel self-limiting growth processes in order to determine the effects on Cmax, frequency dispersion, and midgap trap states.