DRY AND WET ETCHING PROPERTIES OF THERMALLY GROWN SILICON DIOXIDE LAYER AFTER N-IMPLANTATION AND ANNEALING( ION)

We have investigated thermal oxidation of silicon, and dry and wet etc hing characteristics of the oxide layer after N+ (Ar+) ion implantatio n and subsequent annealing. An oxidation resistance is observed in the N+ implanted silicon with doses more than 1 x 10(15) N+/cm2. The etch rate of the oxide layer in a diluted HF solution is enhanced with a d ose of 1 x 10(15) N+/cm2, whereas an etching resistance is observed fo r the samples with doses more than 2 x 10(15) N+/cm2. However, only th e etching resistance appears in the dry etching. These resistances are also observed by argon implantation and easily removed by subsequent annealing. These results indicate that the oxidation and etching resis tances are related to a thin oxynitride formation and the surface modi fication by ion implantation.