Temperature and thermal characteristics of InGaN/GaN vertical light-emitting diodes on electroplated copper

摘要

We report the InGaN/GaN multiple quantum well vertical light-emitting diodes (VLEDs) operating at λ~ 450 nm by the use of laser lift-off and copper electroplating processes. The thermal characteristics of fabricated VLEDs are measured and analyzed in terms of the junction temperature (T_j) using the forward voltage method, which allows us to estimate the thermal resistance (R_(th))- Between 298 and 378 K, the characteristic temperature is measured to be about 903 K at 350 mA. The far-field patterns of the VLED have a uniform and good near-Lambertian emission. The T_j and R_(th) values are also confirmed by the emission peak wavelength shift method. The use of electroplated copper with a high thermal conductivity instead of a sapphire substrate provides much better heat dissipation capability. For a 1 × 1 mm~2 VLED, the low T_j value of 305.8 K is obtained with an output power of 191 mW at an injection current of 350 mA at 298 K, exhibiting R_(th) = 7.98 K W~(-1).