Journal of the Korea Academia-Industrial cooperation Society (한국산학기술학회논문지)

The Korea Academia-Industrial cooperation Society (한국산학기술학회)
권호 표지
DOI QR코드

DOI QR Code

The Improvement for Performance of White LED chip using Improved Fabrication Process

제조 공정의 개선을 통한 백색 LED 칩의 성능 개선

  • Ryu, Jang-Ryeol (Division of Electrical Electronic & Control Eng., Kongju National University)
  • 류장렬 (공주대학교 전기전자제어공학부)
  • Received : 2011.11.30
  • Accepted : 2012.01.05
  • Published : 2012.01.31
Download PDF
⟨ Previous Next ⟩

Abstract

LEDs are using widely in a field of illumination, LCD LED backlight, mobile signals because they have several merits, such as low power consumption, long lifetime, high brightness, fast response, environment friendly. To achieve high performance LEDs, one needs to enhance output power, reduce operation voltage, and improve device reliability. In this paper, we have proposed that the optimum design and specialized process could improve the performance of LED chip. It was showed an output power of 7cd and input supplied voltage of 3.2V by the insertion technique of current blocking layer. In this paper, GaN-based LED chip which is built on the sapphire epi-wafer by selective MOCVD were designed and developed. After that, their performances were measured. It showed the output power of 7cd more than conventional GaN-based chip. It will be used the lighting source of a medical equipment and LCD LED TV with GaN-based LED chip.

LED는 저 전력, 긴 수명, 고 휘도, 빠른 응답, 친환경적인 특성의 여러 장점을 갖고 있기 때문에 청색과 녹색 LED는 교통신호, 옥외 디스플레이, 백색 LED는 LCD 후면광 등의 응용 제품에 사용되고 있다. 여기서 LED의 성능을 향상하기 위하여 출력전력과 소자의 신뢰성을 높이고, 동작전압을 낮추어야 LED 칩의 고효율화가 이루어져야 하는데, 이는 에피택셜층, 표면요철, 패턴이 있는 사파이어 기판, 칩 설계의 최적화, 특수 공정의 개선 등의 기술이 우수해야 한다. 본 연구에서는 측면 에칭 기술과 절연층 삽입기술을 이용하여 사파이어 에피 웨이퍼 위에 GaN-기반 백색 LED 칩을 제작하여 그 성능을 조사하였다. LED 칩의 성능을 개선하기 위한 최적화 설계와 CBL(current blocking layer) 삽입 기술의 개선된 공정을 통하여 LED 칩 성능의 향상을 확인할 수 있었으며, 출력 전력은 광 출력 7cd, 순방향 인가전압 3.2V의 값을 얻었다. 현재의 LCD 후면광원으로 사용되고 있는 LED 칩의 출력에 비하여 성능이 개선되었으며, 의료기기 및 LCD LED TV의 후면광원으로 사용할 수 있을 것으로 기대된다.

Keywords

References

  1. Y. J. Lee, H.C.Kuo, and S.C.Wang "Enhancing the Output Power of GaN-based LEDs Grown on Wet-Etched Pattrened Sapphire Substrates", IEEE PHOTONIC TECHNOLOGY LETTERS, Vol. 18, No. 10, pp. 2289-2291, May 2006.
  2. S. Nakamura and G. Gasol, "The Blue Laser Diode", New York: springer, Vol. 10, No. 3, pp. 223-226, May 1997.
  3. T.Egawa, B.Zhang, and H.Ishikawa, "High Performance of InGaN LEDs on (111) Silicon Substrate grown by MOCVD", IEEE ELECTRON DEVICE LETTERS, Vol. 26, No. 3, pp. 169-171, March 2005. https://doi.org/10.1109/LED.2004.842642
  4. H. G. kim et al, "Improved GaN-Based LED Light Extraction Efficiencies via Selective MOCVD Using Peripheral Microhole Arrays", IEEE PHOTONIC TECHNOLOGY LETTERS, Vol. 20, No. 15, pp. 1284-1286, Aug. 2008.
  5. Y. J. Lee, J. M. Hwang, T. C. Hsu and S.C.Wang, "Study of the Extraction Power Dependent Internal Quentum Efficiency in IngaN/gaN LEDs Grown on Patterned Sapphire Substrate", IEEE Journal of selected Topics in Quantum Electronics, Vol. 15, No. 4, pp. 445-448, Nov. 2009.
  6. Mary H.Crawford, "LEDs for Solid-State Lighting: Performance Challenges and recent Advances", IEEE Journal of selected Topics in Quantum Electronics, Vol. 15, No. 4, pp. 1028-1040, July 2009. https://doi.org/10.1109/JSTQE.2009.2013476
  7. Ivan Elisshevich, "Compound Semiconductor", Vol.6, No.3, pp.82-85, 2000.
  8. Hynsoo Kim, Ji-Myon Lee, Chul Huh, Sang-Woo Kim, Dong-Joon Kim, Seong-ju Park, and Hyunsang Hwang, Appl. phys., Lett. Vol.77, No.12, pp.1903-1906, 2000. https://doi.org/10.1063/1.1311819
  9. C. C. Liu, Y. H. Chen, M. P. Houng, Y. H. Wang, Y. K. Su, W. B. Chen, and S. M. Chen, IEEE Photonics Technol. Lett. Vol.16, pp.1444-1447, 2004. https://doi.org/10.1109/LPT.2004.826786
  10. S.Y.Lee, J.R.Ryu, and S.B.Yoon, "Improvement in light output of LED by using the insulating Blocking layer", KIIT, Vol.9, No.5, pp35-40, 2011.