Investigation of Thin-Film GaNLight-Emitting Diodes with Metal Substrates

• Main Authors: Jun-Sheng Li, 李君聖
• Other Authors: 洪瑞華
• Format: Others
• Language: zh-TW
• Online Access: http://ndltd.ncl.edu.tw/handle/64705352627729090617

碩士 === 國立中興大學 === 精密工程學系所 === 97 === In this study, a vertical conductive structure of thin-film GaN light emitting diode(LED) was prepared by high thermal conductivity copper substrate, laser lift-off (LLO), Ni/Ag mirror with high reflectivity (about 92%), electroplating and wafer bonding technique are demonstrated. In general, vertical type GaN LEDs with high thermal conductive copper substrate were fabricated by electroplating technique. In this thesis, a thin-film GaN LED with copper substrate was also fabricated by wafer bonding process. The forward voltage (@20 mA) of the electroplating copper substrate LEDs, wafer bonding copper substrate LED and conventional LEDs were 2.79 V, 2.80V and 2.82 V, respectively. The forward voltage (@350 mA) of the electroplating copper substrate LEDs, wafer bonding copper substrate LED and conventional LEDs were 3.55 V, 3.60 V and 3.52 V, respectively. The leakage currents (@-5 V) of these devices were also smaller then 1 uA. The output power of electroplating and wafer bonding copper substrate LED were about 4.0 and 2.6 times compared with conventional LEDs. The characteristic of thermal conductivity can be obtained by IR and T3ster system measurement. The surface temperature for electroplating, wafer bonding and conventional device were 43.5 ℃, 45.8 ℃ and 47.5 ℃, respectively, whereas the thermal resistance were 11.1 K/W, 13.2 K/W and 19 K/W, respectively.