Carrier transport mechanism of strained AlGaN/GaN Schottky contacts

• Published in: Current applied physics Vol. 12; no. 4; pp. 1081 - 1083
• Main Authors: Nam, Tae-Chul, Jang, Ja-Soon, Seong, Tae-Yeon
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.07.2012; 한국물리학회
• Subjects: AlGaN/GaN; Aluminum gallium nitrides; Carrier transport; chromium; Density; Gallium nitrides; gold; Leakage current; Polarization; Schottky barrier height; temperature; Temperature dependence; Thermionics; 물리학; Schottky barrier height; Carrier transport; AlGaN/GaN
• ISSN: 1567-1739; 1878-1675
• DOI: 10.1016/j.cap.2012.01.010

Using polarization field effect-based thermionic field emission (PFE-TFE) model based on current–voltage–temperature data, possible carrier transport mechanisms for Pt/Au and Cr/Pd Schottky contacts to Al0.25Ga0.75N/GaN layers were investigated. Thermionic emission (TE) model was also investigated to compare to the PFE-TFE. It was shown that Schottky barrier heights (SBHs) are significantly affected by a polarization field-induced carrier density of the AlGaN layer. In addition, relatively little temperature dependence on the leakage current density of both contacts was found, which is in good agreement with the PFE-TFE model. The results indicate that the TFE is responsible for the current flow across the metal/AlGaN–GaN interface at T ≥ 293 K. ► PFE-TFE model is proposed to investigate the carrier transport mechanism. ► Conventional TE model is also considered to compare to the PFE-TFE. ► Based on J0–T data, the PFE-TFE is dominant for carrier transport at T ≥ 293 K. ► Based on the experimental and theoretical data, qФB and Ns were also obtained.