Executive Summary : | Over the past decade, wide bandgap semiconductors have found increasing use in power electronics. Their use has not only increased the range of operation of the devices but has also made the existing systems much more efficient, compact, and portable. Energy losses during power conversion has also come down significantly. The well-established SiC and GaN-based technologies form the bulk of wide bandgap (WBG) semiconductor usage in these fields, and while they are here to stay, a new class of semiconductors, ultra-wide bandgap (UWBG) semiconductors has shown immense potential for high-power applications. Beta - Gallium Oxide (Beta-Ga2O3) is one such Ultra-wide bandgap semiconductor which given its superior material properties for high power applications as compared to other WBG semiconductors, has become the topic of intense ongoing research. The present proposal presents development of vertical Beta-Ga2O3 FETs with high breakdown voltage, low leakage and large current carrying capability (high performance), high reliability, and simultaneously normally-OFF (enhancement-mode) operation i.e., fail-safe devices. Beta-Ga2O3 transistor technology is still in its infancy therefore this project will also aim at studying the device physics, design challenges, physical reasons behind the device performance and failure modes, and reliability physics. Poor thermal conductivity of Beta-Ga2O3 could lead to severe performance degradation due to self-heating and it going to be a challenge during development of the technology that we also aim to address in the project. Important research and development gap in Beta-Ga2O3 vertical FET technology that will be addressed are: (a)Use of field-plates in order to improve the device breakdown voltage and current carrying capability (b) Use of high-k dielectric with high breakdown field and reliability and improve the dielectric/semiconductor interface to mitigate interface states (c) Use of p-type oxide like NiO and AlTiO to form p-n heterojunction at the trench bottom surface and gate dielectric for reducing the leakage current, improving breakdown voltage and normally-off operation (d) Missing experimental/ computational modelling to study the effect of different parameter like trench width/ height, dielectric material and thickness, possible incorporated field-plate’s length, spacer region, drift region thickness etc. on device performance and reliability (e) Missing extensive thermal characterisation of the device and development of in-device thermal management techniques (f) Missing experimental study on the performance bottlenecks, failure nodes, and reliability physics of the device (g) Better surface electric field management to boost device performance and mitigate early failure |