| 摘要 |
PURPOSE:To enable to set a sheet resistance value to the objective value having favorable precision when P-type impurities are to be diffused by a method wherein Ga is diffused to the prescribed depth in an N-type silicon layer as to make the sheet resisance value to be higher than the objective sheet resistance value, and B is diffused as to obtain the objective sheet resistance value. CONSTITUTION:When the objective sheet resistance value after redistribution is designated by C(OMEGA/?), the sheet resistance value when Ga only is diffused is by A(OMEGA/?), and the resistance value when only B is diffused is by B(OMEGA/?), because the equation 1/A+ or -1/B=1/C can be formed, the value B is calculated by substituting the values A, C to the equation thereof, and diffusion of B is performed in the condition as to make the sheet resistance value after redistribution to become to B(OMEGA/?), and the sheet resistance value is regulated. Because the objective sheet resistance value can be prescribed to some sheet resistance value or more, this method is successful by nearly 100%. Moreover because the sheet resistance value can be regulated accurately to the objective sheet resistance value according to diffusion of B, reproducibility of the sheet resistance value is extremely favorable, and dispersion from the objective value can be suppressed within + or -3%. |
