AVS 45th International Symposium
    Electronic Materials and Processing Division Thursday Sessions
       Session EM-ThP

Paper EM-ThP9
Enhanced Electrical Performance of Au/n-GaN Schottky Diodes by Novel Processing

Thursday, November 5, 1998, 5:30 pm, Room Hall A

Session: Electronic Materials and Processing Poster Session
Presenter: L. He, Northern Illinois University
Authors: L. He, Northern Illinois University
X.J. Wang, University of Maryland at Baltimore County
Correspondent: Click to Email
GaN has attracted great attention recently for its application in electronic and optoelectronic devices. Applications including in blue lasers, visible light emitting diodes (LED), metal-semiconductor field-effect transistor (MESFET), high electron mobility transistors(HEMT), ultraviolet photodetectors, have been demonstrated. Metal/GaN contacts, both ohmic and Schottky, are of important for device applications. Studies of Schottky contacts on GaN were especially interested. Schottky barrier height is expected to be dependent on the metal work function due to the ionic nature of GaN, though the work function of the contact metal is not the exclusive factor determining the Schottky barrier height. In this study, the low temperature (LT = 77K) metal deposition technique was used to improve the electrical characteristics of Au/n-GaN Schottky diode. The LT deposition technique has been successfully used to fabricate high quality Schottky contacts on InP, GaAs and InGaAs. A comparison of the barrier heights is conducted with previously reported results. The same chip of GaN epitaxial layer was used for room temperature (RT) and LT Schottky diodes. The LT Schottky diodes exhibit excellent performance. The leakage current density as low as 2.55x10@super -11@A×cm@super -2@ was obtained from the LT diodes. The linear region in the I-V curve of the LT diodes at forward bias could extend more than eight orders in the magnitude of the forward current. Current-voltage-temperature (I-V-T) measurements were carried out to study the characteristics of the LT diodes. A typical barrier height of 1.32eV for the LT diode was obtained, which is the highest value ever reported. The obvious enhancement in electrical performance makes the LT processing a high promising technique for GaN device application. Analysis through photoluminescence (PL) and x-ray diffraction measurements were conducted to collaborate with the electrical characteristics.