Diamond films have been fabricated on aluminum nitride (AlN) ceramics
by hot filament (HFCVD) method. High nucleation density of more than 1
0(9)/cm(2) can be obtained on AlN wafers by the pre-irradiation of hig
h temperature filament in the hydrogen atmosphere. Thermal properties
of the composites were measured by using photothermal deflection techn
iques (PTD). Thermal diffusivity of diamond film/AlN depends on the qu
ality and thickness of coated diamond films.