Edge termination design and simulation for bulk GaN rectifiers

• Published in: Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Vol. 20; no. 5; pp. 2169 - 2172
• Main Authors: Baik, K. H., Irokawa, Y., Ren, F., Pearton, S. J., Park, S. S., Lee, S. K.
• Format: Journal Article
• Language: English
• Published: 01-09-2002
• Subjects: GaN
• ISSN: 0734-211X; 1520-8567
• DOI: 10.1116/1.1511210

GaN bulk rectifiers show excellent on-state resistances (in the
m
Ω 
cm
−2
range), forward turn-on voltages of ∼1.8 V and reverse-recovery times of <50 ns. A key requirement is to develop effective edge termination techniques in order to prevent premature surface-induced breakdown. We have performed a simulation study of the effects of varying the dielectric passivation material
(
SiO
2
,
SiN
x
,
AlN,
Sc
2
O
3
,
or MgO), the thickness of this material, the extent of metal overlap onto the dielectric and the ramp oxide angle on the resulting reverse breakdown voltage
(V
B
)
of bulk rectifiers. We find that
SiO
2
produces the highest
V
B
of the materials investigated, that there is an optimum metal overlap distance for a given oxide thickness and small oxide ramp angles produce the highest
V
B
.