Indium Gallium Arsenide Three-State and Non-Volatile Memory Quantum Dot Devices

With the silicon technology reaching the end of the Roadmap soon, III-V devices have been researched as possible replacements for silicon. Indium gallium arsenide (InGaAs) is particularly appealing due to its well-established processing protocols in high-speed and high-frequency applications. This dissertation investigates various metal-oxide-semiconductor (MOS) devices using InGaAs as the substrate material. II-VI gate dielectric stacks consisting of ZnSe, ZnS and ZnMgS were used in this research as an alternative to conventional oxide-based gate insulators for InGaAs devices. II-VI gate dielectric materials have been chosen due to their high k values, wider band gaps and similar lattice constants to InGaAs for a lattice-matched semiconductor-insulator interface. Multi-state field-effect transistors were also fabricated incorporating germanium-oxide-cladded germanium quantum dots (QDs) at the gate regions. These QDs have the ability to store charges and providing an additional output state (in additional to the ON and the OFF states). Such QDs can also be used as charge storage centers in non-volatile memory devices, which were also investigated. Integration of quantum well channels in the substrate is another method to provide multi-bit operations, which is discussed in the dissertation. Fabrication process flows, experimental results and modeling simulations of the different fabricated devices are also presented. A look at multi-value logic applications and the future of InGaAs devices are included