InGaAs-InGaN Wafer-Bonded Current Aperture Vertical Electron Transistors (BAVETs)

In this paper, we report the fabrication process and direct-current (DC) characteristics of a wafer-bonded heterostructure-based vertical transistor. It comprises an In_0.53Ga_0.47As/In_0.52Al_0.48As/In_0.53Ga_0.47As field-effect transistor wafer-bonded to a Ga-polar In_0.1Ga_0.9N/GaN template. In the DC-bias operation of this device, the current conduction is initially confined lateral to the InGaAs channel and then flows vertically through a conductive aperture defined in the InGaN/GaN layers. The narrow aperture is isolated by ion-implanted current blocking layer (CBL) regions. The I _d–V _ds characteristics of the device demonstrate transistor-like behavior. Design optimizations have been applied to the implant and doping conditions of the InGaN/GaN layers to eliminate the leakage paths through the CBL while simultaneously obtaining unhindered current conduction through the aperture of the device.