| 摘要 |
PURPOSE:To realize low strains and enhance each value of the ratio of variable capacity and that of variable voltage, by forming a low concentration region on the surface of a semiconductor substrate, a high concentration buried region in the deep layer part of this region and a region of conductive type different from the substrate on the surface layer of the low concentration region. CONSTITUTION:An N<+> Si substrate having the special Miller index with the inclination of 5-8 deg. in the direction of 11-2 from the plane 111 is used for the semiconductor substrate 6, the low concentration region 8 which is the same conductive type as the semiconductor substrate 6 and has impurity atom concentration lower than that of the semiconductor substrate 6 is formed on the surface of the semiconductor substrate 6. The high concentration buried region 10 formed in the deep layer part of the low concentration region 8 is formed by utilizing the implantation of impurity atom ions. After the ion implantation, a diffusion treatment process at 1,100 deg.C for approx. 70min is got through resulting in the formation of the high concentration buried region 10. In this case, since the Si plane inclined at 5-8 deg. in the direction of 11-2 from the plane 111 is used for the semiconductor substrate 6, P atoms are implanted deep in the direction of the semiconductor substrate 6 by channeling effect. The P<+> region 12 of conductive type different from the semiconductor substrate 6 is formed on the surface layer of the low concentration region 8 wherein the high density buried region 10 is formed. |
