| 摘要 |
PURPOSE:To contrive the mass-production of epitaxial wafers having no outward diffusion by diffusing impurities with slow diffusion speed after diffusing impurities having a high diffusion factor. CONSTITUTION:An opening is provided at an SiO3 3 on a P type Si substrate 1 and P (high diffusion speed) is diffused to make an N layer 2. Then, Sb (low diffusion speed) is diffused by applying a predetermined mask and an N layer 4 is stacked on the N layer 2 to push in the N layer 2. At that time, the buried layer 4a of a bipolar transistor for a linear circuit is simultaneously formed. The SiO2 3 is removed by HF to stack an expitaxial layer 5 on the buried layer 4a and an N-P-N transistor in an I<2>L section 21 and an N-P-N transistor in a linear circuit section 22 are formed by a conventional method. In this way, a surface concentration can equally be controlled at a low level by slowly diffusing P at a relatively low temperature prior to As diffusion. And in epitaxial formation, outward diffusion can be reduced at the same extent for ion implantation and the linear and digital circuits having few crystal dettect and good characteristics are provided on one chip easily by using a bipolar element. |
