Defects in AlN ceramics with a thermal conductivity of 102 to 216W/mK were investigated using electron spin resonance. Two ESR signals at g = 2.006 and 1.999 were related to thermal conductivity. The g = 1.999 signal intensity increased with a decrease in thermal conductivity, an increase in O concentration, and an increase in Mg concentration. The g = 1.999 signal was tentatively supposed to be caused by an electron-trapped center. The g = 2.006 signal intensity increased with an increase in thermal conductivity, a decrease in O concentration and an increase in Ca concentration. The defect responsible for the g = 2.006 signal was deduced to be a hole trapped in an ON–VAl complex.

Electron Spin Resonance of Defects Related to Thermal Conductivity in AlN Ceramics. A.Kai, D.Tomohiro, Y.Kanechika, T.Miki: Japanese Journal of Applied Physics, 2008, 47, 6394-8