On-chip very low junction temperature GaN-based light emitting diodes by selective ion implantation

We propose an on-wafer heat relaxation technology by selectively ion-implanted in part of the p-type GaN to decrease the junction temperature in the LED structure. The Si dopant implantation energy and concentration are characterized to exhibit peak carrier density 1×1018 cm-3 at the depth of 137.6 nm after activation in nitrogen ambient at 750 °C for 30 minutes. The implantation schedule is designed to neutralize the selected region or to create a reverse p-n diode in the p-GaN layer, which acts as the cold zone for heat dissipation. The cold zone with lower effective carrier concentration and thus higher resistance is able to divert the current path. Therefore, the electrical power consumption through the cold zone was reduced, resulting in less optical power emission from the quantum well under the cold zone. Using the diode forward voltage method to extract junction temperature, when the injection current increases from 10 to 60 mA, the junction temperature of the ion-implanted LED increases from 34.3 °C to 42.3 °C, while that of the conventional one rises from 30.3 °C to 63.6 °C. At 100 mA, the output power of the ion-implanted device is 6.09 % higher than that of the conventional device. The slight increase of optical power is due to the increase of current density outside the cold zone region of the implanted device and reduced junction temperature. The result indicates that our approach improves thermal dissipation and meanwhile maintains the linearity of L-I curves.

[1]  T. Rozzi,et al.  Interstripe coupling and current spreading in a subthreshold double heterostructure twin stripe laser , 1984 .

[2]  J. Haisma,et al.  Silicon-on-Insulator Wafer Bonding-Wafer Thinning Technological Evaluations , 1989 .

[3]  Han-Youl Ryu,et al.  Measurement of junction temperature in GaN-based laser diodes using voltage-temperature characteristics , 2005, SPIE OPTO.

[4]  E. Schubert,et al.  Junction–temperature measurement in GaN ultraviolet light-emitting diodes using diode forward voltage method , 2004 .

[5]  Jean Paul Freyssinier,et al.  Solid-state lighting: failure analysis of white LEDs , 2004 .

[6]  Shu Yuan,et al.  Performance enhancement of InGaN light-emitting diodes by laser lift-off and transfer from sapphire to copper substrate , 2004 .

[7]  Seong-Ju Park,et al.  Improvement in light-output efficiency of InGaN/GaN multiple-quantum well light-emitting diodes by current blocking layer , 2002 .

[8]  E. F. Schubert,et al.  Current crowding in GaN/InGaN light emitting diodes on insulating substrates , 2001 .

[9]  Tomasz Czyszanowski,et al.  Fully self-consistent three-dimensional model of edge emitting nitride diode lasers , 2003 .

[10]  C. Shih,et al.  Light-emitting diodes with nickel substrates fabricated by electroplating , 2005 .

[11]  Yan-Kuin Su,et al.  Improved light-output power of GaN LEDs by selective region activation , 2004 .

[12]  E. F. Schubert,et al.  Current crowding and optical saturation effects in GaInN/GaN light-emitting diodes grown on insulating substrates , 2001 .

[13]  Yan-Kuin Su,et al.  Fabrication of high-power AlInGaP-based red light emitting diodes with novel package by electroplating , 2007, SPIE OPTO.