Vertical electron transistors with In0.53Ga0.47As channel and N-polar In0.1Ga0.9N/GaN drain achieved by direct wafer-bonding

The design space of conventional semiconductor devices - from the materials point of view - is currently set by heteroepitaxy, whose capability is strongly limited by lattice parameters and structures of materials of interest. Heterostructures of substantially different semiconductors may offer significant advantages in device design, but many of them are likely heteroepitaxy-incompatible. In such cases, direct wafer-bonding can be exploited, in which materials of interest are separately grown and then their heterostructures formed by thermo-compression. InGaAs, with its superior electron mobility and injection velocity, is considered as the best candidate material for achieving electronic devices in THz applications, whereas III-N has proven its promise in high-power applications. Thus, transistors consisting of InGaAs channel and III-N drain may potentially attain both the high-speed and high-power performances. The first bonded aperture vertical electron transistor (BAVET) with In_0.53Ga_0.47As channel and Ga-polar InGaN/GaN drain was demonstrated in 2009 [1], and further improvements on it have also been reported [2], [3]. Here, we demonstrate the first BAVET consisting of In_0.53Ga_0.47As channel and N-polar In_0.1Ga_0.9N/GaN drain, which has an inherent advantage over Ga-polar InGaN/GaN drain, as discussed below.