09:00 〜 09:15
▼ [20a-C200-1] 【Highlighted Presentation】Structural analysis of N-polar InGaN layer grown on ScAlMgO4 substrate without buffer layer
キーワード：III-V Nitrides, InGaN, ScAlMgO4 (SAM)
Lattice-matched ScAlMgO4 (SAM) substrate is the potential candidate for growing a high-quality InGaN layer, which is expected to develop high-In-content InGaN-based red LEDs.[1] The reduction of the in-plane strain in InGaN active region can contribute to improving IQE due to the enhancement of material quality and reduction of QCSE.
Herein, we analyze the crystalline quality of N-polar InGaN layer directly grown on a SAM substrate without a low-temperature buffer layer [2]. The InGaN thin-film was grown by our original MOVPE [3]. The SAM substrate has a 0.2° miscut angle toward the m-axis. Cross-sectional TEM was used to estimate the thickness of the InGaN layer, and it was approximately 220 nm. X-ray rocking curve (XRC) and reciprocal space mapping (RSM) were used to assist strain and the crystalline quality of the InGaN layer. The FWHM of (000–2) plane XRC was 0.2° (720 arcsec) which was two times narrower than the 0.7° reported in the previous literature [1]. Moreover, the RSM satellite exhibited that the InGaN layer was partially relaxed and it corresponds to In0.13Ga0.87N, and it revealed that InGaN layer was maintained with no phase separation. We identified the material polarity by integrated differential phase contrast (iDPC)-STEM. As a result, the InGaN layer indicated N-polar growth. The aforementioned results increases the potential of growing a high crystalline quality N-polar InGaN layer on SAM substrate.
Due to the high In incorporation in N-polar InGaN layer, it is a promising approach to grow the active region for InGaN-based red LED development.
Herein, we analyze the crystalline quality of N-polar InGaN layer directly grown on a SAM substrate without a low-temperature buffer layer [2]. The InGaN thin-film was grown by our original MOVPE [3]. The SAM substrate has a 0.2° miscut angle toward the m-axis. Cross-sectional TEM was used to estimate the thickness of the InGaN layer, and it was approximately 220 nm. X-ray rocking curve (XRC) and reciprocal space mapping (RSM) were used to assist strain and the crystalline quality of the InGaN layer. The FWHM of (000–2) plane XRC was 0.2° (720 arcsec) which was two times narrower than the 0.7° reported in the previous literature [1]. Moreover, the RSM satellite exhibited that the InGaN layer was partially relaxed and it corresponds to In0.13Ga0.87N, and it revealed that InGaN layer was maintained with no phase separation. We identified the material polarity by integrated differential phase contrast (iDPC)-STEM. As a result, the InGaN layer indicated N-polar growth. The aforementioned results increases the potential of growing a high crystalline quality N-polar InGaN layer on SAM substrate.
Due to the high In incorporation in N-polar InGaN layer, it is a promising approach to grow the active region for InGaN-based red LED development.