The low temperature deposition of AlN at 160 °C is examined by using trimethyl aluminum (TMA) and NH radicals from plasma excited Ar diluted ammonia. For the deposition, a plasma tube separated from the reaction chamber is used to introduce the neutral NH radicals on the growing surface without the direct impacts of high-speed species and UV photons, which might be effective in suppressing the plasma damage to the sample surfaces. To maximize the NH radical generation, the NH3 and Ar mixing ratio is optimized by plasma optical emission spectroscopy. To determine the saturated condition of TMA and NH radical irradiations, an in-situ surface observation of IR absorption spectroscopy (IRAS) with a multiple internal reflection geometry is utilized. The low temperature AlN deposition is performed with the TMA and NH radical exposures whose conditions are determined by the IRAS experiment. The spectroscopic ellipsometry indicates the all-round surface deposition in which the growth per cycles measured from front and backside surfaces of the Si sample are of the same range from 0.39∼0.41nm/cycle. It is confirmed that the deposited film contains impurities of C, O, N although we discuss the method to decrease them. X-ray diffraction suggests the AlN polycrystal deposition with crystal phases of AlN (100), (002) and (101). From the saturation curves of TMA adsorption and its nitridation, their chemical reactions are discussed in this paper. In the present paper, we discuss the possibility of the low temperature AlN deposition.

A copper(Cu) thick film conductor containing glass and metal oxide for aluminum niride(AlN) substrate was developed. The conductor showed adhesion strength and reliability which were almost comparable to those of Ag-Pd conductors and also had good solder wettability and erosion properties. The Cu conductors must be fired in a nitrogen atmosphere containing oxygen gas. When they were fired under a low oxygen concentration, the gasses thermally decomposed and their properties changed which meant that the molten gasses could not flow smoothly to the AlN surface, so adhesion strength decreased. On the other hand, under high oxygen concentration, the adhesion strength increased because the thermal decomposition and property changes were suppressed. However, poorer solder wettability was brought about because copper was oxidized. Metal oxide added to the conductor could improve the wettability without decreasing the adhesion strength, even if it was fired at the higher oxygen concentration. Suitable metal oxides were CdO, Co3O5 and Fe2O3.