Composite channel 100 nm InP HEMT with ultrathin barrier for millimetre wave applications

Abstract

This study introduces a High Electron Mobility Transistor (HEMT) designed for millimeter-wave applications, utilizing a composite channel structure based on InP and InGaAs-InAs-InGaAs. The proposed device incorporates an ultra-thin 2 nm barsrier layer, a distinctive composite channel topology, and a judicious selection of III-V materials. These features collectively contribute to an improved confinement of electrons within the channel, thereby improving the concentration of two-dimensional electron gas (2DEG), and consequently, enhancing the mobility and speed of the device. The proposed device exhibits a unity current gain frequency (f T) of 249 GHz and a maximum oscillation frequency (f MAX) of 523.9 GHz, accompanied by a current gain of 67.7 dB at 0.1 GHz. The off-state leakage current is maintained within the nanoampere range, and the minimum noise figure (NF MIN) is merely 0.76 dB at 10 GHz. A comparative analysis of DC and RF performance, along with an examination of associated parasitic elements, is conducted among various composite channel HEMTs proposed in recent literature. A quantitative justification is provided for the superiority of InGaAs-InAs-InGaAs channel HEMTs, establishing their heightened f T and f MAX. The proposed InGaAs-InAs-InGaAs channel HEMTs exhibit 1.4 times improved f T and f MAX, coupled with only half the NF MIN in comparison to their InGaAs-InP-InGaAs channel counterparts. To further comprehend the device’s behavior under varying RF conditions, a frequency-dependent intrinsic Field-Effect Transistor (FET) model is presented. This model facilitates the analysis of the device’s performance and allows the identification of the impact of individual parameters on the overall system.