STEM-Quantum Channel High Breakdown Voltage HEMT
Abstract
A standard approach to improving the performance of power switches and RF transistors is to use ultra-wideband (UWBG) materials such as AlGaN. However, many years of development failed to demonstrate UWBG devices outperforming GaN transistors. The key reason for that is the lower mobility and higher contact resistance of UWBG devices.Our approach is to develop novel quantum channel (QC) devices that use GaN high electron mobility but has a breakdown voltage limited by UWBG layers. This will be achieved using the GaN channel with the thickness of smaller than the electron mean free path sandwiched between the UWBG (AlN or AlGaN or AlInGaN) barrier andUWBG (AlN or AlGaN) substrate. Electrons with low energies (smaller than the conduction band discontinuity) will remain fully localized in the GaN channel. However, the electrons with higher energy wind up in the UWBG cladding layers, where the effective mass andthe density of states are much larger. This is similar to a real space transfer; however, the quantum effect is much stronger because the electron wave function is pushed out of the quantum well region at high electron energies. Using the AlN or AlGaN substrate will avoid premature substrate breakdown and greatly improve heat removal.To further increase the current carrying capability and, therefore, to achieve the ultimate performance will explore additional ways to minimize access and contact resistances of quantum channel devices. We will use a novel #perforated channel# design and novel #perforated field-emission contacts.# Perforated contact design using highly doped GaN perforations separated by distances of the Bohr radius. This contact should achieve tunneling injection. The proposed new QC device design will be experimentally validated by growing Ga-polar and N-polar double-barrier epilayer structuresover AlN and fabricating HEMT devices. We expect the proposed novel device to have peak currents and transconductance close to those of GaN channel HEMTs and breakdown voltage close to UWBG high-Al AlGaN HEMTs.Approved for Public Release
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 03, 2023
- Source ID
- N000142312289
Entities
People
- Michael Shur
Organizations
- Office of Naval Research
- Rensselaer Polytechnic Institute
- United States Navy