| 摘要 |
PURPOSE:To prevent the fall of density of surface impurity in a base region by applying heat treatment in oxidizing ambience for forming an emitter in the condition that a piled boron layer is piled on the surface where Si is exposed. CONSTITUTION:Boron is diffused through the opening of an insulation film 2 on an n-type Si substrate and thereby the base region 3 is formed. Next, the insulation film 2' on the region 3 is opened 4 secondarily wider than a region where the emitter is predetermined to be formed, whereby a part of the surface of the region 3 is exposed. Then, a polycrystalline Si layer 5 and aN Si nitride film 6 which contain n-type diffusion impurity are provided selectively on the surface of the region where the emitter is predetermined to be formed, while the piled boron layer 12 is piled selectively, with the surface density greater than 10<20>/cm<2> and the depth of 300- 1,000Angstrom , on the exposed surface of the region 3. Next, heat treatment being applied in the oxidizing ambience, diffusion of impurity is conducted is conducted from the layer 5 as a source of impurity, whereby an emitter region 7 is formed. On the occasion of this heat tretament for diffusion, boron is added from the layer 12 to the region 3 and thereby the fall of density of the surface impurity in the region 3 is compensated. |
