Abstract: A plasma processing apparatus is provided which includes a plasma reaction chamber in which plasma is generated for processing, an RF power supply for feeding RF power into the plasma reaction chamber through an impedance matching circuit, and a feedback mechanism for maintaining plasma impedance within the plasma reaction chamber substantially constant, the feedback mechanism containing the impedance matching circuit which also functions as impedance sensing means. Also provided is a plasma processing method including the step of etching or depositing films by using plasma, while maintaining plasma impedance substantially constant by applying feedback to at least one selected from the group consisting of gas pressure in the plasma reaction chamber, rate of gas flow into the plasma reaction chamber, magnetic field, microwave power, and RF power.

Abstract: A method of fabricating a semiconductor device having a buried insulator region is constituted by forming ditches in a surface of the buried insulator region to be formed which is closest to the surface of the substrate, implanting ions of gas taken from the group consisting of oxygen and nitrogen into the substrate from the surface to form an ion implanted region corresponding to the desired buried insulator region, and heat treating the thus ion implanted substrate at a gas reaction temperature of at least 1100.degree. C. for forming the buried insulator region.

Abstract: Disclosed is a plasma doping method capable of introducing a large quantity of impurities into a substrate at a relatively low temperature (200.degree. to 600.degree. C.). In the LSI fabrication process represented by Si process, it is necessary to introduce impurities at a properly controlled concentration into desired positions. In this plasma doping method, in order to satisfy this application, the doping temperature may be controlled around 100.degree. C. at high degree of vacuum and by ECR discharge or the like, and a process capable of using a resist mask generally used in the LSI fabrication step and controlling the concentration in a wide range is enabled, so that an extremely shallow impurity profile is realized.

Abstract: A method of fabricating a semiconductor device which includes:(1) a step of forming an opening in a silicon substrate using a first silicon oxide film and a first silicon nitride film formed on the silicon substrate as masks,(2) a step of forming a second silicon oxide film and a second silicon nitride film on the side wall of the opening by the reduced pressure CVD method and anisotropic etching method,(3) a step of performing isotropic dry etching using the first and second silicon oxide films as masks, and(4) a step of performing heat treatment in an oxidizing atmosphere using the first and second silicon nitride films as masks.Thereby, uniform isotropic etching may be accomplished by use of the dry etching method.

Abstract: A large quantity of oxygen (10.sup.18 cm.sup.-3) is dissolved in a semiconductor, for example, a silicon crystal substrate. In particular, in the SOI technology for forming a buried oxide film in silicon by oxygen ion implantation, a large quantity of oxygen (up to 10.sup.20 cm.sup.-3) is left over in the silicon top layer. Such oxygen in the silicon becomes fine precipitates (defects) by the subsequent heat treatment step. Disclosed is, hence, a method for obtaining a semiconductor substrate of high quality by removing impurities by implanting ions containing light element (for example, hydrogen) before heat treatment.