A method for forming a capacitor in a semiconductor body is provided. The method includes the step of forming a trench in a portion of a surface of the semiconductor body. The trench having sidewalls and a bottom. A doped film is deposited over the surface of the semiconductor body. Portions of the doped film are deposited over the sidewalls and bottom of the trench. The semiconductor body is heated and the doped film to produce a liquid phase interface region therebetween while diffusing dopant in the doped film into a region of the semiconductor body. The interface region is cooled to return such interface region to a solid phase. The doped film and the interface region are removed from the semiconductor body while leaving the doped region in the semiconductor body. A dielectric film is deposited over the doped region of the semiconductor body. A doped material is deposited over the dielectric film, the doped material and the doped region in the semiconductor body providing electrodes for the capacitor and the dielectric film providing a dielectric for the capacitor. The heating and cooling steps comprise the steps of: subjecting the semiconductor body and doped film to an energized source of radiant heat to heat such body and doped film and subsequently de-energizing the energized source of radiant heat to cool the doped semiconductor body and doped film. The cooling is at a rate sufficiently rapid to avoid formation of silicon arsenic precipitate.