Carrier transport mechanism of Mg/Pt/Au Ohmic contact on p-GaN/AlGaN/GaN platform with ultra-low resistivity

Tang，Chuying1,2; Fu，Chun1; Jiang，Yang1; He，Minghao1; Deng，Chenkai1,2; Wen，Kangyao1; He，Jiaqi1; Wang，Peiran1; Du，Fangzhou1; Zhang，Yi1; Hu，Qiaoyu1; Tao，Nick3; Wang，Qing1,4,5,6; Yu，Hong Yu1,4,5,6

2023-08-28

10.1063/5.0154841

Applied Physics Letters   Impact Factor & Quartile

0003-6951

1077-3118

In this work, the carrier transport mechanism of Mg/Pt/Au Ohmic contact on p-GaN/AlGaN/GaN with a very low specific contact resistivity of 1.98 × 10Ω cm is investigated. Secondary ion mass spectroscopy measurement results show that the Mg concentration near the p-GaN surface increases form 8 × 10 to 7 × 10/cm for Mg/Pt/Au contact after annealing. It indicates that Mg atoms from the Mg/Pt/Au metal stack diffuse into the p-GaN during annealing, forming a heavily Mg doped p-GaN layer with a depth of about 3 nm. The sheet resistance R depends on temperature for Mg/Pt/Au contacts on p-GaN/GaN, indicating that the influence of 2DHG on carrier transport mechanisms at the metal/p-GaN interface was eliminated. For Mg/Pt/Au contacts at ≥360 K, specific contact resistivity reasonably follows T, which indicates that the band conduction of Schottky theory dominates the carrier transport. For Mg/Pt/Au contacts at 200-360 K, the electrical resistivity reasonably follows T, indicating variable-range hopping (VRH) conduction through Mg-related deep-level defects (DLD). Based on the VRH conduction model, the effective barrier height (qφ) of the Mg-related DLD band is extracted as 0.265 eV, which well matches the excellent Ohmic contact.

SCI

English

NI Journal Papers

First ; Corresponding

This work was supported by Fabrication of Normally-Off GaN Devices based on In situ SiNx Passivation and Selective Area Growth Recessed-Gate Techniques and the Reliability Study (National Natural Science Foundation of China, Grant No. 6227["2023A1515030034","JCYJ20200109141233476","JCYJ20210324120409025","JCYJ20220818100605012"] ; National Natural Science Foundation of China[JCYJ20220530115411025] ; null[62274082]

Physics

Physics, Applied

WOS:001057244000002

AIP Publishing

PHYSICS

2-s2.0-85169978677

Scopus

1.School of Microelectronics,Southern University of Science and Technology,Shenzhen,518055,China
2.Harbin Institute of Technology,Harbin,150006,China
3.Maxscend Microelectrics Company Limited,Wuxi,214072,China
4.Engineering Research Center of Integrated Circuits for Next-Generation Communications,Ministry of Education,Southern University of Science and Technology,Shenzhen,518055,China
5.GaN Device Engineering Technology Research Center of Guangdong,Southern University of Science and Technology,Shenzhen,518055,China
6.Engineering Research Center of Three Dimensional Integration in Guangdong Province,Southern University of Science and Technology,Shenzhen,518055,China

Tang，Chuying,Fu，Chun,Jiang，Yang,et al. Carrier transport mechanism of Mg/Pt/Au Ohmic contact on p-GaN/AlGaN/GaN platform with ultra-low resistivity[J]. Applied Physics Letters,2023,123(9).

Tang，Chuying.,Fu，Chun.,Jiang，Yang.,He，Minghao.,Deng，Chenkai.,...&Yu，Hong Yu.(2023).Carrier transport mechanism of Mg/Pt/Au Ohmic contact on p-GaN/AlGaN/GaN platform with ultra-low resistivity.Applied Physics Letters,123(9).

Tang，Chuying,et al."Carrier transport mechanism of Mg/Pt/Au Ohmic contact on p-GaN/AlGaN/GaN platform with ultra-low resistivity".Applied Physics Letters 123.9(2023).