Advances in p-type and Ambipolar Oxide Semiconductor Materials and Devices for Thin Film Electronics

With the emergence of artificial intelligence, neural networks and autonomous robots, high performance computing technology has become increasingly vital. Heterointegration of thin-film electronics is being actively explored to enable the ongoing development of computing technology. Oxide semiconductors are promising materials for thin-film transistors (TFTs). While n-type oxide semiconductors have already been successfully commercialized in TFT applications, the absence of high-performance p-type oxide semiconductor TFTs limits further development of oxide semiconductor technology. The focus of my research is to investigate p-type and ambipolar SnO and Ta₂SnO₆ film devices to develop a suitable high-performance p-type oxide material.

First, I identified the process window required to achieve p-type SnO using RF sputtering. Through numerical simulation, I determined the dominant limiting factors for relatively poor p-type SnO TFT performance. To address these limitations, I introduced a floating metal capping layer on top of the p-type SnO channel, resulting in record-breaking performance for p-type SnO TFTs. Next, I developed ambipolar SnO TFTs with symmetric n-type and p-type conduction and designed an ambipolar SnO inverter with the highest inverter gain among any ambipolar inverters. Finally, I worked on identifying the process boundaries to achieve p-type Ta₂SnO₆ using a co-sputtering process.

Chair: Professor Becky (R.L.) Peterson