Influence of a deep-level-defect band formed in a heavily Mg-doped GaN contact layer on the Ni/Au contact to p-GaN

Li, Xiaojing; Zhao, Degang; Jiang, Desheng; Chen, Ping; Zhu, Jianjun; Liu, Zongshun; Le, L. C.; Yang, Jing; He, Xiaoliang; Zhang, Liqun; Liu, Jianping; Zhang, Shuming; Yang, Hui

doi:10.1088/1674-1056/24/9/096804

Cited by 4 publications

(3 citation statements)

References 25 publications

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“…A sufficient total p‐GaN thickness is required to accommodate a very highly doped cap layer with a high density of dopants that will provide barrier lowering and thus reducing the specific contact resistivity. However, increasing the thickness further causes poor material quality and dislocations and difficulty in carrier transport that increases the resistivity . Two representative samples of p‐GaN growth temperature of 850 °C (sample A) and 1000 °C (sample B) both of 200 nm total thickness were analysed by SEM and AFM to investigate the surface morphology.…”

Section: Resultsmentioning

confidence: 99%

“…As we discuss later, this high Mg concentration helps to vanish the band bending in the cap layer but is probably too high in the moderate layer for obtaining higher mobility values and hence lower p‐GaN resistivity. Even though the high temperature grown sample shows better crystal quality, to avoid thermal load to the MQW underneath , we need to limit the growth temperature of p‐GaN which is the reason that we chose 850 °C as a good compromise.…”

Section: Resultsmentioning

confidence: 99%

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Investigation of p-contact performance for indium rich InGaN based light emitting diodes and solar cells

Alam

Haas

et al. 2016

Phys. Status Solidi A

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We report on the optimization of p-GaN layers for high indium (In) content InGaN applications by optimizing temperature, precursor CP 2 Mg flow rate and III/V ratio and report also on the optimization of p-contact performance. Using MOVPE, a 150 nm thick p-type GaN with moderate Mg doping and a 50 nm contact layer with high Mg doping concentration were grown on standard GaN templates at growth temperatures in the range of 850-1000 8C. Hall measurement yields hole concentration of 4.8 Â 10 17 cm À3 for the optimized sample. SIMS shows Mg concentration of 1.7 Â 10 20 cm À3 on average in the heavily doped and 4 Â 10 19 cm À3 on average in the moderately doped p-GaN layer for the optimized p-GaN. A multilayer Pd/Ag/Ni/Au metal contact has been deposited on this p-GaN and studied using the CTLM technique. Optimization of both p-GaN layers and p-contact processing led to a low resistance contact with specific contact resistivity of 6 Â 10 À4 Ω cm 2 . We believe, the very high Mg concentration of the surface layer in intimate contact with the contact metal reduces the Schottky barrier height and band bending. This optimization of p-GaN is an important step towards high efficiency green LEDs and solar cells.

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Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Investigation of p-contact performance for indium rich InGaN based light emitting diodes and solar cells

Alam

Haas

et al. 2016

Phys. Status Solidi A

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“…Specific contact resistance ρ c and sheet resistance R SH were carried out through CTLM method. [21] The sheet resistance R SH can be calculated via following formula:…”

Section: Electrical Properties Variations Of P-gan and N-gan Under Hi...mentioning

confidence: 99%

Assessing high-energy x-ray and proton irradiation effects on electrical properties of P-GaN and N-GaN thin films

et al. 2023

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The effects of ionizing and displacement irradiation of high-energy X-ray and 2 MeV proton on GaN thin films were investigated and compared in this study. The electrical properties of both P-GaN and N-GaN, separated from power devices, were gauged for fundamental analysis. It was found that the electrical properties of P-GaN were improved as a consequence of the disruption of the Mg-H bond induced by high-dose X-ray irradiation, as indicated by the Hall and circular transmission line model. Specifically, under a 100 Mrad(Si) X-ray dose, the specific contact resistance ρc of P-GaN decreased by 30%, and the hole carrier concentration increased significantly. Additionally, the atom displacement damage effect of a 2 MeV proton of 1×1013 p/cm2 led to a significant degradation of the electrical properties of P-GaN, while those of N-GaN remained unchanged. P-GaN was found to be more sensitive to irradiation than N-GaN thin film. The effectiveness of X-ray irradiation in enhancing the electrical properties of P-GaN thin films was demonstrated in this study.

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Improvement of Ohmic contact to p-GaN by controlling the residual carbon concentration in p ++ -GaN layer

Liang

Zhao

Jiang

et al. 2017

Journal of Crystal Growth

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Influence of a deep-level-defect band formed in a heavily Mg-doped GaN contact layer on the Ni/Au contact to p-GaN

Cited by 4 publications

References 25 publications

Investigation of p-contact performance for indium rich InGaN based light emitting diodes and solar cells

Investigation of p-contact performance for indium rich InGaN based light emitting diodes and solar cells

Assessing high-energy x-ray and proton irradiation effects on electrical properties of P-GaN and N-GaN thin films

Improvement of Ohmic contact to p-GaN by controlling the residual carbon concentration in p ++ -GaN layer

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