A Study on AlN thin film as Thermal Interface Material for high power LED

AlN thin film was coated over Al and glass substrates with 400 nm thickness using DC sputtering for thermal interface material (TIM) application. AlN coated Al substrate was used as a heat sink for 3W green LED. The thermal transient measurement was recorded for given LED attached with bare Al and AlN coated Al substrate at three different driving currents. The observed junction temperature (TJ) was low ( TJ = 2.81 oC) for AlN coated Al substrate at 700mA compared to bare Al. Thermal paste (TP) was also assisted to reduce the TJ value but created the thermal barrier when applied on AlN thin film. Total thermal resistance (Rth-tot) was also noticeably decreased for AlN thin film. Rth-tot values were high for AlN thin film coated Al substrates at lower driving currents (100 and 350mA) especially at TP condition. Interface resistance was low for AlN thin film as thermal interface material instead of TP.