High-performance camel-gate field effect transistor using high-medium-low doped structure

Abstract

We report an improved camel-gate field effect transistor using a high-medium-low doped channel. A 1000-Å-thick n=1×1017 cm−3 GaAs layer is employed to form the camel gate, which prevents the planar-doped barrier from being dropped abruptly. In addition to transition channel, a thin (200 Å) heavily doped (n=5×1017 cm−3) GaAs layer works as the main active channel to enhance the current drivability and transconductance. For our 1.5×100 μm2 device, the maximum current density of over 850 mA/mm was obtained. Moreover, an enhanced voltage-independent transconductance was also observed. Generally, the device exhibits a transconductance of 220 mS/mm which is compatible to that of MESFETs and is two- or threefold to that of reported camel-gate FETs. In addition, the proposed device demonstrates a large gate voltage swing for high transconductance operation. Due to the excellent device performance, our devices do hold promise for both large signal and digital circuits application, simultaneously.