Abstract: A process for the formation of a cap layer for semiconductors with a low degree of contamination wherein the cap layer is easily formed on the surface of a semiconductor, and binding force thereof with the surface of the semiconductor is strong and stabilized, besides only the cap layer is selectively removed easily, comprises the steps of introducing nitrogen atom into a surface of a semiconductor; combining a component element of the semiconductor in the vicinity of the surface of the semiconductor into which the nitrogen atom has been introduced with the nitrogen atom to form a nitride compound being a compound of the component element of the semiconductor and the nitrogen atom; and utilizing the nitride compound as a cap layer for the surface of the semiconductor.

Abstract: In order to form a fine pattern at high speed with respect to a material such as quartz glass exhibiting a remarkable band gap, having a short wavelength at absorption edge of light, and having high bond energy between constituent atoms, laser beam being transparent as to a material to be worked is irradiated thereupon, at the same time, plasma is produced at a place close to an objective surface of the material to be worked, and ablation is generated on the objective surface of the material to be worked by means of interactions between the plasma and laser beam irradiated upon the material to be worked, thereby to work the material.

Abstract: A multi-mode Raman laser system wherein Raman conversion is performed by injecting exciting laser beam from transversely excited atmospheric pressure CO.sub.2 laser system into a Raman cell. Unstable resonator type oscillator is used as transversely excited atmospheric pressure CO.sub.2 laser system; and multi-mode Raman cell is used as the Raman cell. The quantity required for an excited CO.sub.2 laser system can thus be extensively reduced. Also, it is possible to reduce the input electric required for obtaining the same energy of 16 .mu.m light which is scattered light, because saturated conversion of excited light, can be achieved by multi-mode Raman cell, and system efficiency can be increased.