Fig. 1.
(Color online) Schematic illustration of the contact layer structure and c-TLM pattern used to measure contact resistance.
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Minglong Zhang, Masao Ikeda, Siyi Huang, Jianping Liu, Jianjun Zhu, Shuming Zhang, Hui Yang. Ni/Pd-based ohmic contacts to p-GaN through p-InGaN/p+-GaN contacting layers[J]. Journal of Semiconductors, 2022, 43(9): 092803. doi: 10.1088/1674-4926/43/9/092803
M L Zhang, M Ikeda, S Y Huang, J P Liu, J J Zhu, S M Zhang, H Yang. Ni/Pd-based ohmic contacts to p-GaN through p-InGaN/p+-GaN contacting layers[J]. J. Semicond, 2022, 43(9): 092803. doi: 10.1088/1674-4926/43/9/092803
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Ni/Pd-based ohmic contacts to p-GaN through p-InGaN/p+-GaN contacting layers
doi: 10.1088/1674-4926/43/9/092803
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Abstract
Specific contact resistance$ {\rho }_{\mathrm{c}} $ to p-GaN was measured for various structures of Ni/Pd-based metals and thin (20–30 nm thick) p-InGaN/p+-GaN contacting layers. The effects of surface chemical treatment and annealing temperature were examined. The optimal annealing temperature was determined to be 550 °C, above which the sheet resistance of the samples degraded considerably, suggesting that undesirable alloying had occurred. Pd-containing metal showed ~35% lower$ {\rho }_{\mathrm{c}} $ compared to that of single Ni. Very thin (2–3.5 nm thick) p-InGaN contacting layers grown on 20–25 nm thick p+-GaN layers exhibited one to two orders of magnitude smaller values of$ {\rho }_{\mathrm{c}} $ compared to that of p+-GaN without p-InGaN. The current density dependence of$ {\rho }_{\mathrm{c}} $ , which is indicative of nonlinearity in current-voltage relation, was also examined. The lowest$ {\rho }_{\mathrm{c}} $ achieved through this study was 4.9 × 10–5 Ω·cm2 @ J = 3.4 kA/cm2.-
Keywords:
- GaN,
- ohmic contact,
- specific contact resistance
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References
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