3D Simulation and Optimization of Characteristics of Al0.1Ga0.9N/In0.2Ga0.8N High Electron Mobility Transistor with B0.03Ga0.97N Back-Barrier Layer

The objective of this paper is to simulate the effect of a BGaN back-barrier on performances of a high electron mobility transistor (HEMT) based on AlGaN/InGaN, by using TCAD 3D Silvaco simulator. We simulate some DC and AC characteristics; we note that with only 60 nm BGaN back-barrier layer and 3% of boron in BGaN, HEMT shows improvement of 33.34% in the maximum drain current, 64.7 % in the transconductance, 19% in the threshold voltage, 50% the drain-induced barrier lowering, 34.67% in the subthreshold swing, 20% in the breakdown voltage, 10.18% in the cut-off frequency, 12% in the maximum oscillation frequency, and record high ION/IOFF of over 1012.9.

A Novel 4H-SiC MESFET with a Heavily Doped Region, a Lightly Doped Region and an Insulated Region

A novel 4H-SiC MESFET was presented, and its direct current (DC), alternating current (AC) characteristics and power added efficiency (PAE) were studied. The novel structure improves the saturation current (Idsat) and transconductance (gm) by adding a heavily doped region, reduces the gate-source capacitance (Cgs) by adding a lightly doped region and improves the breakdown voltage (Vb) by embedding an insulated region (Si3N4). Compared to the double-recessed (DR) structure, the saturation current, the transconductance, the breakdown voltage, the maximum oscillation frequency (fmax), the maximum power added efficiency and the maximum theoretical output power density (Pmax) of the novel structure is increased by 24%, 21%, 9%, 11%, 14% and 34%, respectively. Therefore, the novel structure has excellent performance and has a broader application prospect than the double recessed structure.

High-Frequency Limits of Graphene Field-Effect Transistors with Velocity Saturation

The current understanding of physical principles governing electronic transport in graphene field effect transistors (GFETs) has reached a level where we can model quite accurately device operation and predict intrinsic frequency limits of performance. In this work, we use this knowledge to analyze DC and RF transport properties of bottom-gated graphene on boron nitride field effect transistors exhibiting pronounced velocity saturation by substrate hyperbolic phonon polariton scattering, including Dirac pinch-off effect. We predict and demonstrate a maximum oscillation frequency exceeding 20 GHz . We discuss the intrinsic 0.1 THz limit of GFETs and envision plasma resonance transistors as an alternative for sub-THz narrow-band detection.

Physical Insights on the Dynamic Response of SOI n- and p-Type Junc-tionless Nanowire Transistors

This work evaluates, for the first time, the roles of the intrinsic capacitances and the series resistance on the dynamic response of p- and n-type Junctionless Nanowire Transistors. The dynamic behavior evaluation will be carried out through the analysis of the limitation imposed by such parameters on the maximum oscillation frequency (fmax). In the sequence, it will be shown the impacts of fmax and the carriers’ transit time on the minimum switching time presented by JNTs. It has been observed that Junctionless devices present lower fmax than inversion mode transistors of similar dimensions due to higher resistance and lower transconductance. However, the intrinsic capacitances of such devices are smaller than the inversion mode ones, which compensates part of the degradation on fmax caused by the other parameters. Besides that, it is shown that transit time can be important on the dynamic behavior of long devices, but plays a negligible role in shorter ones.