公开(公告)号：JPH0729914A

公开(公告)日：1995-01-31

申请号：JP14012694

申请日：1994-06-22

Applicant: CONS RIC MICROELETTRONICA

Inventor： FUERUTSUCHIO FURISHINA ,  SARUBUATOORE KOTSUFUA

IPC: H01L21/331 ,  H01L29/06 ,  H01L29/167 ,  H01L29/73 ,  H01L29/732

Abstract: PURPOSE: To increase a base-collector breakdown voltage by a method, wherein a heavily doped P-type layer is formed in a deep lightly doped P-type diffused region which extends into a lightly doped N-type layer from a top surface made of acceptor dopant. CONSTITUTION: An aluminum-doped deep P-type region 3 is extended into an epitaxial layer 2 to a depth of about 30-40 μm from a top surface, and a heavily doped P -type region 4 is extended into the deep P-type region 3 to a depth of about 10 μm from the top surface. A base region is composed of the P -type region 4 and the P-type region 3. Three concentric rings 5, 6 and 7, which are composed of aluminum heavily doped P-type regions, are extended into the epitaxial layer 2 from the top surface. The dopant concentration of the ring 5 is higher than the dopant concentration of the ring 6, and the dopant concentration of the ring 6 is higher than the dopant concentration of the ring 7. With this constitution, a base-collector breakdown voltage is increased.