Abstract: A method is provided for diffusion doping of semiconductor chips and wafers, in particular silicon chips and wafers, at peak concentrations of greater than about 3.times.10.sup.19 atoms/cm.sup.3. The semiconducting material to be doped is placed in a furnace wherein the furnace contains an atmosphere of a carrier gas and a dopant containing gas. The doping containing gas is greater than about 0.1 volume percent of the total volume in the furnace chamber. The pressure of the composite gas is greater than about 0.1 Torr. The composite gas has an oxidizing agent concentration of less than about 1 part per million. The method permits the direct doping of a silicon surface to form a shallow n-doped region having a high peak concentration by a diffusion process thereby eliminating damage to the silicon surface from ion implantation which is the commonly used method to achieve these high doping concentrations. Since the method is nondirectional trench sidewalls can be doped at high concentrations.

Abstract: A fabrication method of a semiconductor device is disclosed. Particularly, in the process of forming a gate oxide film on a semiconductor substrate, the method for forming a gate oxide film of a semiconductor device comprises the steps of first-annealing the semiconductor substrate in a nitrogen (N.sub.2) atmosphere; forming a gate oxide film by wet-oxidizing the annealed semiconductor substrate at a low temperature in a mixed gas atmosphere of oxygen (O.sub.2) and hydrogen (H.sub.2); and second-annealing the semiconductor substrate where gate oxide film has been formed, at a high temperature in a nitrogen (N.sub.2) atmosphere. Accordingly, the thinning phenomenon of the gate oxide film near the field oxide film is prevented and the instability such V.sub.FB in the conventional field oxidation method is considerably recovered. Also, the field concentration phenomenon is decreased and tolerance to dielectric breakdown is increased.