In-situ Microscopy of GaN-based Transistor Failure
Abstract
Wide bandgap (such as gallium nitride, GaN) electronics pave the way for high power and high frequency technologies beyond silicon. However, GaN high electron mobility transistors (HEMT) are yet to exhibit the predicted figure of merits and reliability. To address this deficiency, this research project aims to validate the hypothesis that interfaces are the weakest component and diffusion is the dominant degradation mechanism. Interfaces are ubiquitous planar defects, and thus nanoscale in dimension and challenging to isolate from the bulk. Another notable void in the GaN HEMT literature is the non-thermally accelerated physics of failure, such as mechanical stress and electron energy. Accordingly, a unique approach is proposed to isolate the various components of mechanical stress (residual, thermo-elastic and inverse piezo-electric) and study their effects. A novel technology is proposed, where the reliability experiments are performed inside a transmission electron microscope (TEM). Whereas the current art is to identify the degradation mechanisms buried under the data through their signatures, the proposed approach directly visualizes them through atomic resolution imaging, electron diffraction for crystallinity and phase identification and energy dispersion spectroscopy for chemical composition mapping. Fundamental insights from this research will pave the way for aerospace electronics for reduced energy (up to 90 percent less power losses), high-voltage (10x time), high-temperature (2x the maximum temperature), high-frequency (10x) operation compared to silicon-based technology. The proposed research involves active collaboration with the AFRL researchers to enhance mutual intellectual capabilities. The project will enable training of the future workforce through graduate and undergraduate students involved.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 06, 2025
- Source ID
- FA95502410341
Entities
People
- Haque
Organizations
- Air Force Office of Scientific Research
- Pennsylvania State University
- United States Air Force