Effect of dislocations on thermal conductivity of GaN layers

We report calculation of the lattice thermal conductivity in wurtzite GaN. The proposed model is material specific and explicitly includes phonon relaxation on threading dislocations and impurities typical for GaN. We have found that a decrease of the dislocation density by two orders of magnitude in GaN leads to a corresponding increase of the thermal conductivity from 1.31 to 1.97 W/cm K. This theoretical prediction is in very good agreement with experimental data obtained from scanning thermal microscopy. The developed model can be used for thermal budget calculations in high-power density GaN devices. (C) 2001 American Institute of Physics.