Insight into the Al/N-GaN barrier property to realize high quality n-type Ohmic contact

Wang, Ting; Xiong, Zhihua; Zhao, Jingjing; Wu, Ning; Du, Kun; Zhou, Mingbin; Ao, Lei

doi:10.1016/j.jallcom.2019.152855

Cited by 1 publication

(2 citation statements)

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“…The thermal stability of the contact on sample E is better than other samples, which suggests that high carrier concentration maybe plays a possible role in determining the thermal stability of N-face ohmic contact. It was reported that the thermal degradation of ohmic contacts on the N-face of GaN is related to the Ga vacancies (V Ga ) generated during thermal annealing [26]. During the thermal annealing process, the Ga atoms could diffuse into the metal electrode and leave V Ga behind.…”

Section: Thermal Stability Of N-face Ohmic Contactmentioning

confidence: 99%

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HVPE growth of bulk GaN with high conductivity for vertical devices

Xia¹,

Wang²,

Chen³

et al. 2020

Semicond. Sci. Technol.

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The electrical properties of gallium nitride (GaN) substrate are crucial to the performance of vertical power devices. Bulk GaN substrates with carrier concentrations in the range from 6.7 × 1017 to 1.7 × 1019 cm−3 are grown by hydride vapor phase epitaxy. All samples show no obvious tensile stress regardless of the carrier concentration. Moreover, the mobility of Si-doped high-quality bulk GaN is superior to the GaN template with higher dislocation density at the same carrier concentration. The influence of carrier concentration on the performance of ohmic contact on N-face of Si-doped GaN is also carefully studied by circular transfer length measurement and rapid thermal annealing methods. The specific contact resistivity decreases monotonically with increase of carrier concentration, while it increases with the annealing temperature. The N-face contact becomes non-ohmic when the annealing temperature exceeds the limit value, which increases with the carrier concentration. The sample with carrier concentration of 1.7 × 1019 cm−3 still showed ohmic behavior after annealing at 450 °C. These results are not only useful to improve the electrical properties of N-type bulk GaN substrate, but also provide a potential solution for improving the efficiency of vertical devices in the future.

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Section: Thermal Stability Of N-face Ohmic Contactmentioning

confidence: 99%

“…However, the mechanism for the poor ohmic contact to Nface is still unclear, which may be concerned with point defects and surface topography [21,26].…”

Section: Introductionmentioning

confidence: 99%