FABRICATION METHOD FOR TRIPLE WELL OF SEMICONDUCTOR DEVICE

摘要

PURPOSE: A method for manufacturing a triple well of a semiconductor memory device is provided to improve an electrical characteristic of a triple well by performing a simplified process. CONSTITUTION: A pad oxide layer(205) is formed on a semiconductor substrate(200) of a P type. The first well(210) of P-type is defined by forming the first mask pattern. The first well(210) of P-type is formed by implanting P-type dopant ions. The second mask pattern is formed on the semiconductor substrate(200). The first well(330) of N-type is formed on a peripheral region and a sidewall(342) is formed on a memory cell array region by implanting N-type dopant ions. The third mask pattern(444M) is formed on the substrate(200). A base region(444) is formed by implanting N-type dopant ions. The second well(440) of N-type is formed by the base region(444).