[paper] Heterojunction Nano-HEMT

G. Purna Chandra Rao1, Trupti Ranjan Lenka2, Valeria Vadalà3

and Hieu Pham Trung Nguyen4

Characteristics Study of Heterojunction III-Nitride/β-Ga2O3 Nano-HEMT for THz Applications

Eng. Res. Express (2024) in press
DOI: 10.1088/2631-8695/ad3db1

1 Electronics and Communication Engineering, NIT Silchar, Assam (IN)

2 Electronics and Communication Engineering, NIT Silchar, Assam (IN)

3 Physics, University of Milan-Bicocca (IT)

4 Electrical and Computer Engineering, Texas Tech University (USA)

Abstract: In this research study, a recessed gate III-Nitride high electron mobility transistor (HEMT) grown on a lattice matched β-Ga2O3 substrate is designed. This research investigation aims to enhance DC and RF performance of AlGaN/GaN HEMT, and minimize the short-channel effects by incorporating an AlGaN back layer and field plate technique, which can enhances electron confinement in two-dimensional electron gas (2DEG). A precise comparison analysis is done on the proposed HEMT’s input characteristics, output characteristics, leakage current characteristics, breakdown voltage properties, and RF behaviour in presence and absence of AlGaN back layer in regard to field plate configuration. The inclusion of back barrier aids in raising the level of conduction band, which reduces leakage loss beneath the buffer, and aids in keeping the 2DEG to be confined to a narrow channel. Furthermore, the field plate design offers an essential electric field drift between gate and drain, resulting to enhanced breakdown voltage characteristics.

FIG : Epitaxial schematic illustration of suggested III-nitride HEMT with the proposed back barrier and field plates.

Acknowledgment : The authors acknowledge SERB (Science and Engineering Research Board), Govt. of India sponsored Mathematical Research Impact Centric Support (MATRICS) project no. MTR/2021/000370 for support.

[tutorial] next generation 3D nano device simulator

Single-electron transistor - laterally defined quantum dot - 3D Tutorial

Stefan Birner

https://www.nextnano.com

Single-electron transistor - laterally defined quantum dot In this tutorial, we simulate an AlGaAs/GaAs heterostructure grown along the z direction. This structure leads to a two-dimensional electron gas (2DEG). By appying a gate voltage on top of the structure in the (x,y) plane, one is able to deplete the 2DEG and a laterally defined QD is formed. By adjusting the gate voltage, one is able to tune the number of electrons that are inside the QD.

This figure shows the conduction band edge Ec(x,y) and the electron density n(x,y) for the 2DEG plane, i.e. at z = 8 nm below the GaAs/AlGaAs heterojuntion. The geometry of the top gates is indicated by the blue regions. The following figure shows the calculated conduction band edge and the electron density of the heterostructure. The results are similar to Fig. 4 in paper [1].

The following figure shows two 2D slices through the lateral (x,y) plane at a distance of 8 nm below the AlGaAs/GaAs interface. In the middle, the electron density is shown. The electron density has been calculated classically. At the bottom, the conduction band edge is shown. The results are similar to Fig. 5 in paper [1]. At the top, the four gates are shown.

REF:

[1] A. Scholze, A. Schenk, W. Fichtner; Single-Electron Device Simulation; IEEE TED 47, 1811 (2000)