Performance enhancement of normally-off Al2O3/AlN/GaN MOS-Channel-HEMTs with an ALD-grown AlN interfacial layer

• Published in: 2014 IEEE 26th International Symposium on Power Semiconductor Devices & IC's (ISPSD) pp. 362 - 365
• Main Authors: Liu, Shenghou, Yang, Shu, Tang, Zhikai, Jiang, Qimeng, Liu, Cheng, Wang, Maojun, Chen, Kevin J.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01.06.2014
• Subjects: Aluminum gallium nitride; Aluminum oxide; Gallium nitride; HEMTs; III-V semiconductor materials; Logic gates; Threshold voltage
• ISBN: 9781479929177; 1479929174
• ISSN: 1063-6854; 1946-0201
• DOI: 10.1109/ISPSD.2014.6856051

In this work, the performance of GaN-based MOS-Channel-HEMTs (MOSC-HEMTs) are shown to be greatly improved by a thin ALD-grown AlN interfacial layer inserted between the amorphous Al 2 O 3 gate dielectric and GaN-channel. The single-crystalline AlN interfacial layer effectively blocks oxygen from the GaN surface and avoids the formation of detrimental Ga-O bonds. Frequency-dispersion in C-V characteristics has been effectively suppressed. The maximum drain current and field-effect mobility are boosted from 410 mA/mm and 98 cm 2 /V·s in a conventional Al 2 O 3 /GaN MOSC-HEMT to 660 mA/mm and 165 cm 2 /V·s in an Al 2 O 3 /AlN/GaN MOSC-HEMT, owing to improved interface quality. The devices also deliver a high ON/OFF current ratio of ∼10 10 , and significantly reduced dynamic on-resistance degradation.