| 摘要 |
PURPOSE:To improve the alignment accuracy and to prevent defects in insulating properties and breakdown strength, by patterning a nitride film formed by means of the CVD process to provide exposure registration patterns so that the registration patterns are covered with polysilicon deposited thereon and thereby prevented from shifting during epitaxial growth. CONSTITUTION:A silicon nitride film 1 is formed on a clean substrate surface by means of plasma and thermal CVD processes. Subsequently, the silicon nitride film is removed by the dry etching process except its portions corresponding to exposure registering patterns. After the substrate surface is cleaned, a dopant containing film 3 is formed by applying an SOD liquid (solution containing a dopant) with a dopant coater. Patterned resist is used as a mask so that unrequired part of the film 3 is removed and the resist is removed by ashing the same. Then, an oxide film (SOG)4 is provided by the spin-on process so that it prevents automatic doping of the dopant. The substrate is then heat treated at a temperature of 1200 deg.C or over in the atmosphere of nitrogen used also as a mask of insulating boron containing 0-5 % of oxygen, so that an impurity diffused layer 5 is formed thereby. The oxide film is removed and an epitaxial layer 8 is formed by the epitaxial growth. |
