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

Abstract

Boron-doped aluminum nitride (B-AlN) 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-AlN 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-AlN thin film (prepared at process 4) interfaced LED showed low R th-tot and T j value for all driving currents and observed high difference in R th-tot (DR th-tot = 2.2 K/W) at 700 mA when compared with the R th-tot of LED attached on bare Al substrates (LED/Al). The T j of LED was reduced considerably and observed 4.7°C as DT j for the film prepared using process 4 condition when compared with LED/Al boundary condition at 700 mA. The optical performance of LED was also tested for all boundary conditions and showed improved lux values for the given LED at 700 mA where B-AlN 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-AlN thin film as efficient solid thin film thermal interface materials in high power LED.

Novel boron‐rich aluminum nitride advanced ceramic materials

“…Considering previous studies of B–Al–N solid solution, the theoretical investigation was conducted for a 6.25% concentration of the Al in the BN 103 . BN nanotubes, nanosheets, and monolayers were doped with Al 104–106 and investigated theoretically and experimentally synthesized in the form of thin films 107,108 . Moreover, the structural and electronic properties of the B x Al 1− x N ( x = .6, .25, .50 .75) solid solution were investigated by first‐principle calculations, but only for the wurtzite structure type 109,110 .…”

“…103 BN nanotubes, nanosheets, and monolayers were doped with Al [104][105][106] and investigated theoretically and experimentally synthesized in the form of thin films. 107,108 Moreover, the structural and electronic properties of the B x Al 1−x N (x = .6, .25, .50 .75) solid solution were investigated by first-principle calculations, but only for the wurtzite structure type. 109,110 Similarly, the influence of the addition of boron on the mechanical, electronic, and thermodynamical properties was investigated theoretically focusing on the cubic phase of AlN (sphalerite structure type).…”