Quantum Capacitance in N-Polar GaN/AlGaN/GaN Heterostructures

Author

Park, Pil Sung ; Nath, Digbijoy N. ; Rajan, Siddharth

Author_Institution

Dept. of Electr. & Comput. Eng., Ohio State Univ., Columbus, OH, USA

Volume

33

Issue

7

fYear

2012

fDate

7/1/2012 12:00:00 AM

Firstpage

991

Lastpage

993

Abstract

We investigate the effects of quantum capacitance in an N-polar GaN/AlGaN/GaN heterostructures by directly measuring quantum displacement of the electron wavefunction Δd. A comparison between electrically and microscopically measured thicknesses showed negative quantum displacement effects in the inverted high-electron-mobility-transistor (HEMT) structure. As a result of the quantum capacitance effects, a quantum displacement Δd of ~ -4nm was extracted from the measurements. Further analysis using 1-D self-consistent Schrodinger-Poisson solver has been done to validate the measured data. Our simulation results, including multiple-subband occupancy, explain the increasing capacitance in the measured C-V profile in N-polar GaN-based HEMTs.

Keywords

III-V semiconductors; Poisson equation; Schrodinger equation; aluminium compounds; gallium compounds; high electron mobility transistors; wide band gap semiconductors; 1D self-consistent Schrodinger-Poisson solver; GaN-AlGaN-GaN; HEMT; N-polar heterostructures; electron wavefunction; inverted high-electron-mobility-transistor structure; measured C-V profile; multiple-subband occupancy; negative quantum displacement effects; quantum capacitance effects; Aluminum gallium nitride; Gallium nitride; HEMTs; Logic gates; Quantum capacitance; Thickness measurement; AlGaN/GaN high-electron-mobility transistor (HEMT); N-polar GaN; capacitance–voltage ($C$–$V$ ); negative quantum; quantum capacitance; quantum displacement;

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/LED.2012.2196973

Filename

6203554