Microstructure of Ti/Al and Ti/Al/Ni/Au ohmic contacts for n-GaN

被引:255
作者
Ruvimov, S
LilientalWeber, Z
Washburn, J
Duxstad, KJ
Haller, EE
Fan, ZF
Mohammad, SN
Kim, W
Botchkarev, AE
Morkoc, H
机构
[1] UNIV CALIF BERKELEY,DEPT MAT SCI & MIN ENGN,BERKELEY,CA 94720
[2] UNIV ILLINOIS,COORDINATED SCI LAB,URBANA,IL 61810
[3] UNIV ILLINOIS,MAT RES LAB,URBANA,IL 61810
关键词
D O I
10.1063/1.117060
中图分类号
O59 [应用物理学];
学科分类号
摘要
Transmission electron microscopy has been applied to characterize the structure of Ti/Al and Ti/Al/Ni/Au Ohmic contacts on n-type GaN (similar to 10(17) cm cm(-3)) epitaxial layers. The metals were deposited either by conventional electron-beam or thermal evaporation techniques, and then thermally annealed at 900 degrees C for 30 s in a N-2 atmosphere. Before metal deposition, the GaN surface was treated by reactive ion etching. A thin polycrystalline cubic TiN layer epitaxially matched to the (0001) GaN surface was detected at the interface with the GaN substrate. This layer was studied in detail by electron diffraction and high resolution electron microscopy. The orientation relationship between the cubic TIN and the GaN was found to be: {111}(TiN)//{00.1}(GaN), [110](TiN)//[11.0](GaN), [112](TiN)//[10.0](GaN). The formation of this cubic TiN layer results in an excess of N vacancies in the GaN close to the interface which is considered to be the reason for the low resistance of the contact. (C) 1996 American Institute of Physics.
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页码:1556 / 1558
页数:3
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