Low-resistance ohmic contacts to p-type GaN achieved by the oxidation of Ni/Au films
Low-resistance ohmic contacts to p-type GaN achieved by the oxidation of Ni/Au films
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DOI：
10.1063/1.371392
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发表时间：
1999-10-15
影响因子：
3.2
通讯作者：
Kai, JJ
中科院分区：
文献类型：
--
作者：
Ho, JK;Jong, CS;Kai, JJ
已经开发了接触以实现与p型GaN的低比接触电阻。该接触由沉积在p型GaN上的双层Ni/Au膜组成，随后在空气中热处理以将金属Ni转化为NiO沿着非晶Ni-Ga-O相和大的Au晶粒。在500 ℃时，接触电阻率低至4.0 × 10（-6）Ω cm（2）。通过优化Ni/Au膜厚度和热处理温度获得了该低值。在低于约400 ℃时，Ni未被完全氧化。另一方面，在高于约600 ℃的温度下，由于NiO从p-GaN脱离并且形成的非晶Ni-Ga-O相的量多于在500 ℃下退火的样品，所以比接触电阻增加。利用Au/p-NiO/p-GaN结构的能带图模型解释了氧化Ni/Au薄膜获得低电阻欧姆接触的机理。(C)1999年美国物理学会。[S0021-8979（99）00820-8]。
A contact has been developed to achieve a low specific contact resistance to p-type GaN. The contact consisted of a bi-layer Ni/Au film deposited on p-type GaN followed by heat treatment in air to transform the metallic Ni into NiO along with an amorphous Ni-Ga-O phase and large Au grains. A specific contact resistance as low as 4.0x10(-6) Omega cm(2) was obtained at 500 degrees C. This low value was obtained by the optimization of Ni/Au film thickness and heat treatment temperatures. Below about 400 degrees C, Ni was not completely oxidized. On the other hand, at temperatures higher than about 600 degrees C, the specific contact resistance increased because the NiO detached from p-GaN and the amount of amorphous Ni-Ga-O phase formed was more than that of the sample annealed at 500 degrees C. The mechanism of obtaining low-resistance ohmic contacts for the oxidized Ni/Au films was explained with a model using energy band diagrams of the Au/p-NiO/p-GaN structure. (C) 1999 American Institute of Physics. [S0021-8979(99)00820-8].