| 학회 | 한국재료학회 |
| 학술대회 | 2008년 가을 (11/07 ~ 11/07, 차세대융합기술연구원) |
| 권호 | 14권 2호 |
| 발표분야 | 제 15회 신소재 심포지엄 - 조명용 백색 LED기술 |
| 제목 | 고휘도 조명용 광반도체 LED 소자공정 |
| 초록 | GaN and related compounds are receiving great attention as optoelectronic devices such as light emitting diodes (LEDs). Achievement of high luminous intensity by flip-chip LEDs (FCLEDs) with Ag reflector or using top emitting LEDs (TELEDs) with highly transparent ITO contacts is required to improve the external quantum efficiency (EQE) and light output of LED. However, since the work function of Ag and ITO is lower than 5.0 eV, it is difficult to produce low-resistance p-type electrode with Ag or ITO only. In this study, in order to develop new ohmic contact materials having low contact resistance and high transmittance, nano-particle embedded p-type electrodes for FCLEDs or TELEDs were suggested. In case of the p-type electrodes for FCLEDs, we developed ZnNi and MIO based nano-particle ohmic contact materials. The nano-particle-structured ZnNi/Ag p-type electrode showed very low contact resistance of ~10–6 Ωcm2 and high output power. As for the p-type electrodes for TELEDs, we developed Ag and CIO based nano-particle ohmic contact materials. The luminous intensity of side-view-packaged white LED fabricated with the CIO/ITO, which are used as a back-light of LCD in cellular phone, was as high as 1.1 cd at 20 mA. This result strongly suggests that CIO/ITO can serve as highly promising p-type electrode for the fabrication of high brightness TELEDs. Finally, to elucidate the mechanism for forming a low resistance ohmic contact by the nano-particle structured ohmic contact materials, we proposed the carrier transport model in which the carriers flow from the metal directly to the dense deep level defect band, and also suggested that a formation of inhomogeneous Schottky barriers at the p-GaN/Ag reflector or p-GaN/ITO interface due to the breaking-up of the ohmic contact materials may increase current flow, followed by further reduction of contact resistance. |
| 저자 | 곽준섭 |
| 소속 | 국립순천대 |
| 키워드 | LED; GaN; 소자제조공정 |
