Control of Bowing in Free-standing GaN Substrate by Using Selective Etching of N-polar Face

N-polar면의 선택적 에칭 방법을 통한 Free-standing GaN 기판의 Bowing 제어

  • Received : 2015.11.23
  • Accepted : 2015.12.21
  • Published : 2016.01.01


In this paper, we report that selective etching on N-polar face by EC (electro-chemical)-etching effect on the reduction of bowing and strain of FS (free-standing)-GaN substrates. We applied the EC-etching to concave and convex type of FS-GaN substrates. After the EC-etching for FS-GaN, nano porous structure was formed on N-polar face of concave and convex type of FS-GaN. Consequently, the bowing in the convex type of FS-GaN substrate was decreased but the bowing in the concave type of FS-GaN substrate was increased. Furthermore, the FWHM (full width at half maximum) of (1 0 2) reflection for the convex type of FS-GaN was significantly decreased from 601 to 259 arcsec. In the case, we confirmed that the EC-etching method was very effective to reduce the bowing in the convex type of FS-GaN and the compressive stress in N-polar face of convex type of FS-GaN was fully released by Raman measurement.


GaN;Electro-chemical etching;Bowing;Freestanding GaN;Wet process


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