Method for surface modification and apparatus therefor

Abstract

A substrate to be modified is placed in a vacuum vessel, a reducing atmosphere is provided over the substrate and simultaneously therewith the substrate is irradiated with accelerated ions, whereby oxygen which bonds to the substrate is freed from the substrate, the oxygen bonds to a material which forms the reducing atmosphere and the surface of the substrate is modified by the accelerated ion. The surface of the substrate can be thus efficiently modifed at relatively low temperatures. Furthermore, by evaporating carbon for an alumina substrate or alumina powder or providing hydrocarbon gas over the alumina substrate or alumina powder in a vacuum vessel, the alumina substrate or alumina powder is providing in the reducing atmosphere and the alumina substrate or alumina powder is irradiated with accelerated nitrogen ions from an ion source, whereby aluminum and oxygen which constitute the alumina substrate or alumina powder are cut off from each other by irradiation with the accelerated nitrogen ions. The oxygen reacts with carbon or hydrocarbon gas which forms the reducing atmosphere to form carbon monoxide or carbon dioxide, which is evacuated. On the other hand, the aluminum is modified to aluminum nitride by the accelerated nitrogen ions or nitrogen particles. That is, the surface of the alumina substrate or alumina powder can be efficiently modifed at relatively low temperatures.