Temperature-dependent contact resistivity of the nonalloyed ohmic contacts to p-GaN
Temperature-dependent contact resistivity of the nonalloyed ohmic contacts to p-GaN
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DOI：
10.1063/1.1691178
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发表时间：
2004-05
影响因子：
3.2
通讯作者：
J. Kwak;O. Nam;Yongjo Park
中科院分区：
文献类型：
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作者：
J. Kwak;O. Nam;Yongjo Park
研究了非合金Pd/Pt/Au与p-GaN薄膜的接触电阻率随温度的变化以及p-GaN薄膜的薄层电阻率随温度的变化，以了解考虑到Pd和p-GaN之间较大的功函数差异而导致的极低的接触电阻率（10−4 Ω cm 2）。随着测量温度从300 K降低到100 K，接触电阻率增加了一个数量级以上。此外，薄层电阻率随exp（To/T）1/4线性增加，这意味着通过深能级缺陷（DLD）的可变范围跳跃传导。p-GaN薄膜中DLD的密度估计超过1019 cm-3，这表明载流子可能从Pd直接流向致密的DLD，导致极低的接触电阻率。
Temperature-dependent contact resistivity of nonalloyed Pd/Pt/Au contacts to p-GaN films as well as temperature-dependent sheet resistivity of p-GaN films has been investigated in order to understand anomalously low contact resistivity (∼10−4 Ω cm2) considering the large work-function difference between the Pd and p-GaN. As the measured temperature decreases from 300 to 100 K, the contact resistivity increases by more than one order of magnitude. In addition, the sheet resistivity increases linearly with exp(To/T)1/4, implying variable-range hopping conduction via deep-level defects (DLDs). The density of the DLDs in the p-GaN films is estimated to be over 1019 cm−3, which suggests that the carriers may flow from the Pd directly to the dense DLDs, resulting in the anomalously low contact resistivity.