Recess-Free Nonalloyed Ohmic Contacts on Graded AlGaN Heterojunction FETs

Author

Pil Sung Park ; Krishnamoorthy, Sriram ; Bajaj, Sanyam ; Nath, Digbijoy N. ; Rajan, Siddharth

Author_Institution

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

Volume

36

Issue

3

fYear

2015

fDate

Mar-15

Firstpage

226

Lastpage

228

Abstract

We report on a new approach to achieve nonalloyed ohmic contacts with record low resistance in GaN-based transistors. We use upward and reverse grading of Al composition in a polarization-graded field-effect transistor structure to eliminate abrupt heterojunction band offsets and create direct contact to the channel. Total contact resistance of 73 mQ · mm and interfacial resistance of 29 mQ · mm to the 2-D electron gas were obtained. The method adopted here could enable to ultralow-resistance contacts without ohmic recess.

Keywords

III-V semiconductors; aluminium; contact resistance; field effect transistors; gallium compounds; ohmic contacts; two-dimensional electron gas; wide band gap semiconductors; 2D electron gas; alluminium composition; direct contact; graded heterojunction FET; heterojunction band offset elimination; interfacial resistance; polarization-graded field-effect transistor structure; recess-free nonalloyed ohmic contacts; record low-resistance; reverse grading; total contact resistance; ultralow-resistance contacts; upward grading; Aluminum gallium nitride; Contact resistance; Gallium nitride; HEMTs; MODFETs; Ohmic contacts; Resistance; FETs; GaN; HEMTs; HFETs; PolFETs; graded; nonalloyed; ohmic contacts; polarization grading; regrowth;

fLanguage

English

Journal_Title

Electron Device Letters, IEEE

Publisher

ieee

ISSN

0741-3106

Type

jour

DOI

10.1109/LED.2015.2394503

Filename

7015567