Performance and direct-coupled FET logic applications of InAlAs/InGaAs co-integrated field-effect transistors by 2-D simulation

Based on the InAlAs/InGaAs heterostructure doping-channel field-effect transistors (DCFETs), three co-integrated devices are demonstrated. After removing some material layers, the enhancement/depletion-mode devices and inverter logic were formed. The InAlAs/InGaAs co-integrated structures consist of an enhancement-mode device with single channel and two depletion-mode devices with double and triple channels, respectively. The insertion of an undoped large energy-gap layer between the metal gate and active channels can improve the gate breakdown voltage and turn-on voltage. Besides, by the studied integrated DCFETs two transfer characteristics are implemented for direct-coupled FET logic (DCFL) circuit applications as compared to the previous reports with only single logic transfer characteristic. Consequently, the integrated AlInAs/GaInAs DCFETs provide a promise for signal amplification and multiple inverter logic applications.