In:
MRS Proceedings, Springer Science and Business Media LLC, Vol. 512 ( 1998)
Abstract:
We report on the dry etching damage effects on the Ohmic contact characteristics of Sidoped n -type GaN. The 2-µm thick n -type GaN samples whose carrier concentrations are ∼7 × 10 17 /cm 3 are grown on c-plane sapphire substrates by metalorganic chemical vapor deposition(MOCVD). The samples are processed to measure the transmission line method(TLM). We evaporated Ti/Al/Ni/Au=150/2700/400/4000 Å on the samples using an ebeam evaporator under 5 × 10 −7 torr and annealed at 700 °C for lminute using a rapid thermal annealer(RTA). AES and XPS data show that the surface stoichiometry of the sample etched with H 2 gas is gallium- richer than that of the one etched with Cl 2 gas. According to the previous report[l], N-vacancy acts as shallow donor in GaN. However, specific contact resistivity of the sample etched with H 2 gas is 3.03 × 10 −6 Ω cm 2 , which is much higher than that of the sample etched with C1 2 gas, 7.9 × 10 −7 Ω cm 2 . The difference of the N- vacancy formed during the etching process cannot completely explain the result. We suggest that formation of Ga x O y during etching process, and the weakening of the bonding by ion bombardments might be responsible for the difference in the ohmic characteristics.
Type of Medium:
Online Resource
ISSN:
0272-9172
,
1946-4274
DOI:
10.1557/PROC-512-495
Language:
English
Publisher:
Springer Science and Business Media LLC
Publication Date:
1998
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