The paper presents the results concerning the formation of a ‘barrier’ layer on AlN ceramic during its joining with copper by the Copper Direct Bonding (CDB) technique. Prior to the joining, the AlN surface was modified by isothermal oxidation or by titanium ion implantation. The effects of the oxidation process temperature were examined within the temperature range from 673 to 1473K. The surface of the ceramic was modified by titanium ion implantation at various ion doses and various accelerating voltages. The modified ceramic was joined with oxidized copper in a nitrogen atmosphere with about 1.5ppm of oxygen, using a belt-type furnace at a temperature of 1323K. The microstructure and phase changes induced on the surfaces of the joints were examined. The modification yielded a ‘barrier’ layer (TiN), which ensured a continuous pore-less contact between the materials being joined. The results obtained under all the experimental conditions indicate that the implantation gives better effects than thermal oxidation. Ion implantation seems to be ideally suited for these purposes. The preferential dose appears to be 5*E16ions/cm2 and the preferential accelerating voltage – 15kV.