Integrated Electronics on Aluminum Nitride Materials and Devices

This thesis outlines the principles, device physics, and technological applications of electronics based on the ultra-wide bandgap semiconductor aluminum nitride. It discusses the basic principles of electrostatics and transport properties of polarization-induced two-dimensional electron and hole channels in semiconductor heterostructures based on aluminum nitride. It explains the discovery of high-density two-dimensional hole gases in undoped heterojunctions, and shows how these high conductivity n- and p-type channels are used for high performance nFETs and pFETs, along with wide bandgap RF, mm-wave, and CMOS applications. The thesis goes on to discuss how the several material advantages of aluminum nitride, such as its high thermal conductivity and piezoelectric coefficient, enable not just high performance of transistors, but also monolithic integration of passive elements such as high frequency filters, enabling a new form factor for integrated RF electronics.

Chapter 1. Introduction.- Chapter 2. Polarization-induced 2D Hole Gases in undoped (In)GaN/AlN Heterostructures.- Chapter 3. GHz-speed GaN/AlN p-channel Heterojunction Field Effect Transistors.- Chapter 4. Polarization-induced 2D Electron and Holes in undoped AlN/GaN/AlN Heterostructures.- Chapter 5. AlN/GaN/AlN High Electron Mobility Transistors.- Chapter 6. Integrated RF Electronics on the AlN Platform.

Dr. Reet Chaudhuri is a Logic Device Engineer at the Intel Corporation, where he uses semiconductor device physics for developing next-generation semiconductor transistors to keep Moore’s Law alive. Reet earned his Ph.D. in 2021 in semiconductor device physics at Cornell University, USA under the guidance of Prof Debdeep Jena, working at the intersection of solid-state physics, electronics and materials science. His doctoral research work focused on enabling integrated high-frequency electronics on the aluminum nitride (AlN) platform through careful material growth and electronic device development. His scientific discovery of the long-missing undoped mobile holes in gallium nitride in 2019 led to new insights into wide bandgap semiconductor physics, and enabled record high speed transistors crucial for future, energy-efficient electronics. During the course of his PhD, Reet has co-authored 20+ journal papers, 20+ conference presentations, 6 invited talks and 4 patents; including highimpact works in Science and IEEE IEDM. He also has also co-founded a semiconductor start-up venture Soctera Inc. commercializing his research work on high-frequency signal amplifiers using aluminum nitride. More information can be found on his website www.reetchaudhuri.com.