Performance of Chemical Vapor Deposited Boron-Doped AlN Thin Film as Thermal Interface Materials for 3-W LED: Thermal and Optical Analysis

Boron-doped aluminum nitride(B-Al N)thin films were synthesized on Al substrates by using chemical vapor deposition method by changing the synthesis parameters and were used as thermal interface material for high power light emitting diode(LED).The B-Al N thin film-coated Al substrate was used as heat sink and studied the performance of high power LED at various driving currents.The recorded transient cooling curve was evaluated to study the rise in junction temperature(T_j),total thermal resistance(R_(th-tot))and the substrate thermal resistance(R_(th-sub))of the given LED.From the results,the B-Al N thin film(prepared at process 4)interfaced LED showed low R_(th-tot)and T_jvalue for all driving currents and observed high difference in R_(th-tot)(DR_(th-tot)=2.2 K/W)at 700 m A when compared with the R_(th-tot)of LED attached on bare Al substrates(LED/Al).The T_jof LED was reduced considerably and observed 4.7°C as DT_jfor the film prepared using process 4 condition when compared with LED/Al boundary condition at 700 m A.The optical performance of LED was also tested for all boundary conditions and showed improved lux values for the given LED at 700 m A where B-Al N thin film was synthesized using optimized flow of Al,B and N sources with minimized B and N content.The other optical parameters such as color correlated temperature and color rendering index were also measured and observed low difference for all boundary conditions.The observed results are suggested to use B-Al N thin film as efficient solid thin film thermal interface materials in high power LED.