Novel Selective Area Growth with PAMBE applied to GaN Vertical Epitaxial Processing for Development of High-Efficiency Power Devices
Abstract
Gallium nitride (GaN) is a promising candidate to supersede silicon (Si) and silicon carbide (SiC) as the standard for power electronic devices. When considering new materials for power device applications, candidates are assessed on several criteria; one could argue that most vital to these criteria are the critical electric field and electron mobility of the candidate. Large critical field strength and high electron mobility are important for high-voltage and high-frequency applications, the bread-and-butter of power devices. GaN is superior to its competitors in both categories. This is not to say GaN is a miracle material, there are still issues with GaN processing that plague its performance and advancement into the market. Industry standard processing methods are not compatible with GaN if it is to give its best performance. Dry etching and ion implantation techniques introduce harmful defects into GaN which degrade device performance; furthermore, p-doping, which is essential to master for high-efficiency switches and diodes, is still a challenge. Precursor-reliant growth methods suffer from compensating impurities, requiring post processing techniques to activate p-type charge carriers; these patchwork solutions increase cost and time of processing. Success has come in the form of selectivearea growth (SAG) techniques which reduce the use of etching processes, and in the form of alternative growth methods such as Plasma-Assisted Molecular Beam Epitaxy (PAMBE) which eliminate precursors from the growth and doping equations. Motivated by the rising standards for power device performance, the research presented herein describes the novel technique of Silicon-Nitride-Shadowed (SNS)SAG as an enabling technology for GaN vertical epitaxial processing. SNS-SAG counters the prevailing downfalls of traditional SAG. We demonstrate the capabilities of PAMBE-SNS-SAG as it applies to tall and smooth features, whose performance in Schottky diodes surpasses industry standard etching techniques, and as it applies to novel device designs for which we present extensive simulation. Weoutline the schedule for further development of PAMBE-SNS-SAG to accommodate super-micron features, and expand the technology to field effect transistors (FETs), and a suite of advanced dual-conduction diodes.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Aug 05, 2021
- Source ID
- N000142112544
Entities
People
- Kyekyoon Kim
Organizations
- Office of Naval Research
- United States Navy
- University of Illinois Urbana–Champaign