MANUFACTURE OF TRANSISTOR

摘要

PROBLEM TO BE SOLVED: To provide a method for manufacturing a transistor for improving the operating speed of a circuit by preventing decrease in characteristics of a short-channel transistor having a long channel by channel ion implantation for improving the characteristics of the transistor, reducing the difference of threshold voltages in a chip to obtain satisfactory circuit characteristics, moreover reducing the size of a minimum transistor usable for improving a short- channel effect, and increasing the saturated current of the transistor. SOLUTION: A channel ion implantation for improving the characteristics of a short-channel transistor is executed to only an active region 2 for forming the transistor with a mask layer 5 used as a mask. Thereafter, ion implantation for optimizing threshold of both the active regions 2, 3 for forming the short- channel transistor and a long-channel transistor is executed.