Abnormal dependence of contact resistivity on hole concentration in nonalloyed ohmic contacts to p-GaN
Abnormal dependence of contact resistivity on hole concentration in nonalloyed ohmic contacts to p-GaN
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DOI：
10.1063/1.1478154
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发表时间：
2002-05
影响因子：
4
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与p-GaN的接触电阻率对空穴浓度的依赖关系。通过改变p-GaN中的Mg浓度[Mg]来改变空穴浓度。[Mg]为4.5×1019 cm-3的p-GaN显示出2.2×1017 cm-3的空穴浓度，其中接触电阻率测量为8.9×10 - 2 Ω cm 2。当[Mg]增加到1.0×1020 cm−3时，空穴浓度显著降低到2.0×1016 cm−3。然而，p-GaN上的Pd接触显示出低至5.5×10−4 Ω cm 2的接触电阻率。接触电阻率对空穴浓度的异常依赖性可以通过在Pd/p-GaN界面处通过深能级缺陷带而不是价带的主导电流来解释。
The dependence of contact resistivity on hole concentration has been investigated for nonalloyed Pd contacts to p-GaN. The hole concentration was varied by changing the Mg concentration, [Mg], in p-GaN. The p-GaN having the [Mg] of 4.5×1019 cm−3 showed the hole concentration of 2.2×1017 cm−3, where contact resistivity was measured as 8.9×10−2 Ω cm2. When the [Mg] increased to 1.0×1020 cm−3, the hole concentration was significantly reduced to 2.0×1016 cm−3. Nevertheless, the Pd contacts on the p-GaN displayed contact resistivity as low as 5.5×10−4 Ω cm2. The abnormal dependence of contact resistivity on hole concentration may be explained by predominant current flow at the Pd/p-GaN interface through a deep level defect band, rather than the valence band.