InGaAs/GaAsSb Quantum-well Tunnel-FET for Ultra-low Power Applications

The Tunnel-FET (TFET), where carrier injection is determined by gate-controlled tunneling from the source to the channel, has been attractive as one of the promising candidates for future ultra-low power applications. In this thesis, inline-TFETs with tunneling direction aligned to the gate electric field are designed, fabricated and analyzed based on ultrathin InGaAs/GaAsSb quantum-wells (QWs). The fabricated QWTFETs show temperature independent SS below 140 K, indicating the achievable tunneling current steepness with the current device design. Analyses with physical modeling and quantum simulations reveal the fundamental gate efficiency around 55-64 % and the ultimate intrinsic tunneling steepness of the InGaAs/GaAsSb tunneling junction around 30 mV/dec. Optimization on gate efficiency suggests 1.4 X improvement with reasonable design parameters, projecting 38 mV/dec SS at low temperature. Non-logic TFET-specific circuits are also explored to understand the advantage of TFETs in real-world applications. The demonstration of QWTFET-based RF detector, oscillator and RF mixer show the potential of QWTFET in these non-logic circuit applications, especially for ultra-low standby power applications.