Title: Toward AlGaN channel HEMTs on AlN: Polarization-induced 2DEGs in AlN/AlGaN/AlN heterostructures

Abstract

Due to its high breakdown electric field, the ultra-wide bandgap semiconductor AlGaN has garnered much attention recently as a promising channel material for next-generation high electron mobility transistors (HEMTs). A comprehensive experimental study of the effects of Al composition x on the transport and structural properties is lacking. We report the charge control and transport properties of polarization-induced 2D electron gases (2DEGs) in strained AlGaN quantum well channels in molecular-beam-epitaxy-grown AlN/Al _x Ga _{1− x} N/AlN double heterostructures by systematically varying the Al content from x = 0 (GaN) to x = 0.74, spanning energy bandgaps of the conducting HEMT channels from 3.49 to 4.9 eV measured by photoluminescence. This results in a tunable 2DEG density from 0 to 3.7 × 10 ¹³ cm ² . The room temperature mobilities of x ≥ 0.25 AlGaN channel HEMTs were limited by alloy disorder scattering to below 50 cm ² /(V.s) for these 2DEG densities, leaving ample room for further heterostructure design improvements to boost mobilities. A characteristic alloy fluctuation energy of [Formula: see text] eV for electron scattering in AlGaN alloy is estimated based on the temperature dependent electron transport experiments.

Authors:

Singhal, Jashan  ^[1];

• Search DOE PAGES for author "Singhal, Jashan"
• Search DOE PAGES for ORCID "0000-0002-1454-8515"

Chaudhuri, Reet  ^[1];

• Search DOE PAGES for author "Chaudhuri, Reet"
• Search DOE PAGES for ORCID "0000-0002-6562-4506"

Hickman, Austin ^[1]; Protasenko, Vladimir ^[1]; Xing, Huili Grace  ^[2];

• Search DOE PAGES for author "Xing, Huili Grace"
• Search DOE PAGES for ORCID "0000-0002-2709-3839"

Jena, Debdeep  ^[2]

• Search DOE PAGES for author "Jena, Debdeep"
• Search DOE PAGES for ORCID "0000-0002-4076-4625"

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+ Show Author Affiliations

1. School of Electrical and Computer Engineering, Cornell University, Ithaca, New York 14853, USA
2. School of Electrical and Computer Engineering, Cornell University, Ithaca, New York 14853, USA, Department of Materials Science and Engineering, Cornell University, Ithaca, New York 14853, USA, Kavli Institute at Cornell for Nanoscale Science, Cornell University, Ithaca, New York 14853, USA

Publication Date:

Tue Nov 01 00:00:00 EDT 2022

Sponsoring Org.:

USDOE

OSTI Identifier:

1899637

Grant/Contract Number:  

SC0021230

Resource Type:

Publisher's Accepted Manuscript

Journal Name:

APL Materials

Additional Journal Information:

Journal Name: APL Materials Journal Volume: 10 Journal Issue: 11; Journal ID: ISSN 2166-532X

Publisher:

American Institute of Physics

Country of Publication:

United States

Language:

English