p-GaAs/n-Ga2O3 heterojunction diode with breakdown voltage of ∼800 V
Shuwen Xie, Moheb Sheikhi, Shining Xu, Md Tahmidul Alam, Jie Zhou, L. J. Mawst, Zhenqiang Ma, Chirag Gupta
Abstract
As an attractive next generation ultrawide bandgap material, Ga2O3 has been demonstrated to be capable of high voltage operation. However, the lack of shallow p-type dopant in Ga2O3 leads to difficulties in developing Ga2O3 based bipolar devices. The semiconductor grafting technology, by bonding a single crystalline p-type semiconductor nanomembrane (NM) to n-Ga2O3 to from abrupt heterojunction, offers a way to expand the application of Ga2O3 in bipolar areas. In this Letter, we report a p-GaAs/(001)-Ga2O3 heterojunction diode fabricated using semiconductor grafting technology. The single crystalline GaAs NM was prepared and transferred onto a Ga2O3 substrate, showing good integrity. Diodes of a mesa diameter of 25 μm were fabricated, showing a high breakdown voltage of ∼800 V, a power figure of merit of 126.5 MW/cm2, and a calculated 1D peak electric field of 1.60 MV/cm. The turn on voltage of the diode was determined to be around 1.91 V with an on–off ratio to be 6 × 106 at −4/4 V and the specific on resistance to be 5.06 mΩ cm2. The ideality factor was extracted to be approximately 1.34, indicating reasonable interface quality. The interfacial defects and the self-passivation effects of Ga2O3 are discussed, and the theoretical band diagram was analyzed for the p-GaAs/n-Ga2O3 heterojunction. By managing the peak electric field with suitable edge termination techniques, higher breakdown voltage can be expected. In addition, by taking advantage of the InGaAsP alloy system, a wide variety of GaAs-Ga2O3 based high voltage HBT can be further developed.