JSTS:Journal of Semiconductor Technology and Science

  • 제16권2호
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  • Pages.179-184
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  • 2016
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  • 1598-1657(pISSN)
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  • 2233-4866(eISSN)
대한전자공학회 (The Institute of Electronics and Information Engineers)
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Contact Resistance and Leakage Current of GaN Devices with Annealed Ti/Al/Mo/Au Ohmic Contacts

  • Ha, Min-Woo (Department of Electrical Engineering, Myongji University) ;
  • Choi, Kangmin (Department of Electrical Engineering, Myongji University) ;
  • Jo, Yoo Jin (Department of Advanced Materials Engineering, Hanyang University) ;
  • Jin, Hyun Soo (Department of Materials Science & Chemical Engineering, Hanyang University) ;
  • Park, Tae Joo (Department of Advanced Materials Engineering, Hanyang University)
  • 투고 : 2015.08.25
  • 심사 : 2015.11.23
  • 발행 : 2016.04.30
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초록

In recent years, the on-resistance, power loss and cell density of Si power devices have not exhibited significant improvements, and performance is approaching the material limits. GaN is considered an attractive material for future high-power applications because of the wide band-gap, large breakdown field, high electron mobility, high switching speed and low on-resistance. Here we report on the Ohmic contact resistance and reverse-bias characteristics of AlGaN/GaN Schottky barrier diodes with and without annealing. Annealing in oxygen at $500^{\circ}C$ resulted in an increase in the breakdown voltage from 641 to 1,172 V for devices with an anode-cathode separation of $20{\mu}m$. However, these annealing conditions also resulted in an increase in the contact resistance of $0.183{\Omega}-mm$, which is attributed to oxidation of the metal contacts. Auger electron spectroscopy revealed diffusion of oxygen and Au into the AlGaN and GaN layers following annealing. The improved reverse-bias characteristics following annealing in oxygen are attributed to passivation of dangling bonds and plasma damage due to interactions between oxygen and GaN/AlGaN. Thermal annealing is therefore useful during the fabrication of high-voltage GaN devices, but the effects on the Ohmic contact resistance should be considered.

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참고문헌

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