AVS 47th International Symposium
    Semiconductors Friday Sessions
       Session SC+EL-FrM

Paper SC+EL-FrM10
GaN and AlGaN Power Rectifiers

Friday, October 6, 2000, 11:20 am, Room 306

Session: III-Nitride Processing and Devices
Presenter: A.P. Zhang, University of Florida
Authors: A.P. Zhang, University of Florida
G. Dang, University of Florida
F. Ren, University of Florida
X.A. Cao, University of Florida
K.P. Lee, University of Florida
S.J. Pearton, University of Florida
J. Han, Sandia National Laboratories
J.I. Chyi, National Central University,Taiwan
C.M. Lee, National Central University, Taiwan
C.C. Chuo, National Central University, Taiwan
Correspondent: Click to Email
We fabricated the GaN & AlGaN rectifiers and p-i-n rectifiers on a range of different MOCVD-grown materials. The reverse breakdown voltages of lateral GaN&AlGaN rectifiers on 3µm thick resistive GaN&AlGaN were in a range of 2.3~4.3kV with a 30µm Schottky metal and Ohmic metal spacing. The p-i-n diodes on 4µm thick GaN epitaxial layer showed a reverse breakdown voltage of 500V with turn-on voltage of ~5V (100A/cm@super 2@). Different edge termination methods were used to improve the performance of GaN rectifiers, including Schottky metal overlap, guard rings, and float rings and junction barrier control (JBS). The edge termination has a strong effect to prevent catastrophic breakdown at the contact periphery. The lowest R@sub ON@ was 0.14 @ohm@.cm@super 2@ for GaN rectifiers and 2.6 @ohm@.cm@super 2@ for AlGaN rectifiers. Figure-of-merit (V@sub RB@)@super 2@/R@sub ON@ are in the 6 -55 MW.cm@super -2@ range, emphasizing the potential of these devices for power switching applications. For the devices we fabricated, we invariantly observed the negative temperature coefficient for V@sub RB@ most likely due to the influence of defects in the heteroepitaxial GaN. For the similar reverse breakdown voltage, current densities are higher in the p-i-n structures, at the expense of higher turn-on voltage, but the on-voltages still need improvement in the Schottky rectifiers. A comparison will be given with state-of-the-art Si and SiC power rectifiers.