| 摘要 |
PURPOSE:To obtain a shallow N type conductive layer which has the excellent junction characteristics and contact characteristics by a method wherein the dosage in the 1st ion-implantation is suppressed in order to obtain a shallow diffusion layer and the dosage in the 2nd ion-implantation is large enough to give the sufficient impurity density and the 1st ion-implantation and heat treatment and the 2nd ion-implantation and heat- treatment are carried out separately. CONSTITUTION:In the procedure of forming an N type conductive layer 2 by adding an arsenic or phosphorous impurity to a prescribed region of a silicon substrate, at first the 1st ion-implantation, in which arsenic or phosphorous ions are implanted with the dosage rate of 1X10<12>-5X10<14> ions/cm<2>, and the 1st heat-treatment at the temperature range of 800-900 deg.C are carried out. Then the 2nd ion-implantation, in which arsenic ions are implanted with the dosage rate of 1X10<15>-5X10<16> ions/cm<2>, and the 2nd heat- treatment at the temperature range of 500-900 deg.C are carried out. With this constitution, a shallow diffusion layer is obtained by the 1st ion-implantation with the suppressed dosage and the 1st heat-treatment at the relatively high temperature and at the same time the excellent contact characteristics are obtained by the 2nd ion-implantation with the sufficient dosage and the 2nd heat-treatment at the relatively low temperature. |
