고효율 질화갈륨계 발광 다이오드용 전자선 증착 ITO 투명 전도 전극 연구

• Published in: 대한금속·재료학회지, 46(10) Vol. 46; no. 10; pp. 683 - 690
• Main Authors: 서재원, Jae Won Seo, 오화섭, Hwa Sub Oh, 강기만, Ki Man Kang, 문성민, Seong Min Moon, 곽준섭, Joon Seop Kwak, 이국회, Kuk Hwe Lee, 이우현, Woo Hyun Lee, 박영호, Young Ho Park, 박해성, Hae Sung Park
• Format: Journal Article
• Language: Korean
• Published: 대한금속재료학회 22.10.2008; 대한금속·재료학회
• Subjects: electron beam evaporator; ITO; LED; ohmic contact; 재료공학
• ISSN: 1738-8228; 2288-8241

In order to develop transparent electrodes for high efficiency GaN-based light emitting diodes (LEDs), the electrical and optical properties of the electron beam evaporated ITO contacts have been investigated as a function of the deposition temperature and flow rate of oxygen during the deposition. As the deposition temperature increases from 140℃ to 220℃, the resistivity of the ITO films decreases slightly from 4.0×10-4 Ωcm to 3.3×10-4 Ωcm, meanwhile the transmittance of the ITO films significantly increases from 67% to 88% at the wavelength of 470 nm. When the flow rate of oxygen during the deposition increases from 2 sccm to 4 sccm, the resistivity of the ITO films increases from 3.6×10-4 Ωcm to 7.4×10-4 Ωcm, meanwhile the transmittance of the ITO films increases from 86% to 99% at 470 nm. Blue LEDs fabricated with the electron beam evaporated ITO electrode show that the ITO films deposited at 200℃ and 3 sccm of the oxygen flow rate give a low forward-bias voltage of 3.55 V at injection current of 20 mA with a highest output power.