Investigation of Current-Voltage Characteristics of Ni/GaN Schottky Barrier Diodes for Potential HEMT Applications

Authors Ashish Kumar1 , Seema Vinayak2, R. Singh1

1 Indian Institute of Technology Delhi, Hauz Khas, 110016, New Delhi, India

2 Solid State Physical Laboratory, Timarpur, 110054, Delhi, India

Issue Volume 3, Year 2011, Number 1, Part 4
Dates Received 04 February 2011, in final form 13 October 2011, published online 17 October 2011
Citation Ashish Kumar, Seema Vinayak, R. Singh, J. Nano- Electron. Phys. 3 No1, 671 (2011)
PACS Number(s) 73.30. + y, 73.40.Ei, 73.40.Sx
Keywords GaN (35) , Schottky diode (10) , Thermionic (3) , Current-voltage (17) , XRD (90) , AFM (18) .
In the present work, the I-V characteristics of Ni/GaN Schottky diodes have been studied. The Schottky diodes, having different sizes using Ni/Au and ohmic contacts using Ti/Al/Ni/Au were made on n-GaN. The GaN was epitaxially grown on c-plane sapphire by metal organic chemical vapor deposition (MOCVD) technique and had a thickness of about 3.7 µm. The calculated ideality factor and barrier height from current-voltage (I-V) characteristics (at 300 K) for two GaN Schottky diodes were close to ~1.3 and ~ 0.8 eV respectively. A high reverse leakage current in the order of 10 – 4A/cm2 (at – 1 V) was observed in both diodes. A careful analysis of forward bias I-V characteristics showed very high series resistance and calculation for ideality factor indicated presence of other current transport mechanism apart from thermionic model at room temperature.

List of References