Research For Real Space Transfer Transistor

One important direction in integrate circuit is to improve the degree of integration. Because of its high frequency,high speed and controllable NDR, the RSTT can be integrated with HEMT or other compound devices to make up of high-speed integrate circuit, and this will be a further research on new material and new structure.At first in this paper the subject background and research progress is introduced, and then the design idea, materials structure, the fabrication ofδ-doped GaAs/InGaAs gated dual-channel structure RSTT is explained in detail and the I-V characteristics are measured. Finally, the RSTT is simulated by using the ATLAS software.RSTT is a device of N-type negative differential resistance, which realizes the decrease of mobility or diffluence by utilizing transfer of electrons in the real space in order to cause NDR. When the energy of electrons is higher than the potential barrier it can get to the gate, even when the gate voltage is given. The two channels are U-shaped quantum well formed by InGaAs channel and V-shaped quantum well formed byδ-doping channel. Two mechanisms are responsible for transport of hot electron, i.e., thermionic emission from U-shaped quantum well to V-shaped quantum well at lower gate voltage and thermally assisted tunneling from channels to gate at higher gate voltage. Compared with results of the fabrication, two mechanisms have been simulated separately, and the negative resistance characteristic and the transconductance characteristic of GaAs based RSTT have been carried on analysis. The influence of the material parameter and the design parameter to the negative resistance characteristic is analyzed, and then the essential parameter as cap layer and spacer layer are optimized to search development direction.