The Inverse Piezoelectric Effect (IPE) is thought to contribute to possible device failure of GaN High Electron Mobility Transistors (HEMTs). Here we focus on a simulation study to probe the possible mitigation of the IPE by reducing the internal electric fields and related elastic energy through the use of high-k materials. Inclusion of a HfO2 “cap layer” above the AlGaN barrier particularly with a partial mesa structure is shown to have potential advantages. Simulations reveal even greater reductions in the internal electric fields by using “field plates” in concert with high-k oxides.
Nagulapally, D., Joshi, R., & Pradhan, A. K. (2015). Simulation Study of HEMT Structures with HfO2 Cap Layer for Mitigating Inverse Piezoelectric Effect Related Device Failures. AIP Advances (international Journal), 017103 (5 pages). https://doi.org/10.1063/1.4905702