YIP Switching Dynamics and Reliability Physics of Multidimensional Power Devices
Abstract
Low-cost, efficient, and reliable power devices are central to improving the power conversion efficiency in many naval applications. The performance of power device relies on both semiconductor material and device architecture. While wide-bandgap (WBG) semiconductors have improved power devices, multidimensional device architectures-such as superjunction, multi-channel and multi-gate technologies-recently rewrote the theoretical limits of WBG power devices. Compared to conventional power devices that block voltage in the direction of current conduction, multidimensional devices introduce electrostatics engineering in at least one additional geometrical dimension. They can process higher power at higher frequency with smaller loss and, therefore, are widely regarded as the next generation of WBG devices.Despite the breakthrough static performance, fundamental knowledge gaps exist on the switching dynamics and reliability physics of multidimensional power devices. Due to the electrostatics tailoring in additional dimensions, the carrier dynamics within the device during the nanosecond switching transient are much more complicated, particularly under high voltage/current slew rates. Also, multidimensional devices usually comprise more material interfaces. The traps and defects at these interfaces, together with the time-dependent ionization of the deep-level dopants in WBG semiconductors, can pose new limitations on the device switching speed and reliability.This project aims at probing the transient dynamics and reliability physics of multidimensional power devices under high current density (>500 A/cm2), high slew rate (>100 V/ns), high electric field (E-field > 2 MV/cm), and high temperature (>175 oC). An integrated research approach is proposed to combine multi-physics mixed-mode simulation and modeling, as well asthe transformative circuit-based switching tests. Gallium nitride (GaN) multi-channel and superjunction are selected as two demonstrative vehicles, which are representatives of the lateral and vertical multidimensional devices. This project highlights two key innovations. First, an on-wafer circuit test platform will be developed to directly characterize the device dynamics in the inductive-load, nanosecond switching transient. Today such power circuit test is mainly performed on the board level for packaged devices. In comparison, the proposed on-wafer circuit test platform will a) provide fast and direct feedback on the impact of device designs, material properties, and fabrication processes on the device switching speed and reliability; b) provide an easy interface for failure analysis; and c) enable high-temperature switching characterizations up to 200-300 oC, which will not be hindered by difficulties inthe development of high-temperature packaging. Second, a multi-physics dynamic simulation and modeling platform will be establishedfor multidimensional power devices. Device-circuit mixed-mode, electrothermal device simulations that include trapping effect will be deployed to understand the carrier dynamics and device electrostatics in the switching process. This understanding will be the foundation for probing and predicting the device stability, reliability, and robustness in power switching applications. This project has multifaceted impacts. Scientifically, it will build a knowledge base that correlates the nanoscale material/interface propertiesto the complex device characteristics under away-from-equilibrium, dynamic conditions. For Navy, this project will establish a unified characterization and simulation platform that is applicable to all emerging WBG and ultra-wide bandgap power devices that are being developed in multiple naval projects. This platform will bridge the gap between new device development and power electronics applications. NRL will be a collaborator of this project. The major learnings from this project will be transferred to NRL at the end of the project.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Mar 15, 2024
- Source ID
- N000142412227
Entities
People
- Yuhao Zhang
Organizations
- Office of Naval Research
- United States Navy
- Virginia Tech