Thermal transient characteristics of die attach in high power LED PKG

Improved thermal management for GaN power electronics: Silver diamond composite packages

“…Good agreement between simulation and experimental data was achieved using a die-attach thermal conductivity of 40 W/(m K). This value is within the range of solder thermal conductivity (20-60 W/(m K)) that can be found in literature [16][17][18][19], with the difference that our value was extracted using Raman thermography which is more accurate than the often used electrical method to determine device temperature which does not measure peak device temperature [20]. Therefore, it is worthwhile to take advantage from this accurately validated model to extract the temperature drop in each layer and their contribution to the overall thermal resistance of the packaged device.…”

Improved heat dissipation in gallium nitride light-emitting diodes with embedded graphene oxide pattern

“…In LED packaging, T j and R th are the two physical quantities generally considered for the evaluation of heat dissipation. Therefore, to explore the extent of heat dissipation that the rGO can give, the above two parameters were studied using transient thermal analysis 40,41 (see Methods for more details). Figure 6a shows the transient cooling curves of the LED packages obtained at 150 mA driving current.…”

“…For conventional LED on sapphire, when the chip is mounted on a heat-sink, most of the heat flows from the active region through n-type cladding layer and the sapphire substrate to the heat-sink by conduction, and only a fraction of heat flows by convection means at surface-air boundaries 41,43 . In this structure, heat transfer to the heat-sink is slowed down because of the poor thermal conductivity of sapphire (38 W mK À 1 ).…”

Thermal Management and Interfacial Properties in High-Power GaN-Based Light-Emitting Diodes Employing Diamond-Added Sn-3 wt.%Ag-0.5 wt.%Cu Solder as a Die-Attach Material

“…Recently, high-power GaN-based LEDs have attracted much attention and are considered candidates for next-generation general illumination applications due to their high luminous efficiency, long operating life, energy savings, and so forth. 1 However, a power saturation phenomenon 2 was often encountered in the operation of GaN-based LEDs packaged with silver paste when the current injection level was raised. This is because the thermal conductivity of silver paste is poor and the heat generated from LEDs was not being efficiently dissipated, resulting in reduced conversion efficiency with increasing junction temperature.…”

“…However, interfacial reactions in LED packaging employing SAC305 solder have rarely been studied. 2 Therefore, the other focus of this study is on the interfacial reactions in LED packaging.…”