Manufacturing method for raising new property of semiconductor element

[0017] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

[0018] 1a to 1d are cross-sectional views for explaining the steps of the method of manufacturing a semiconductor element according to the embodiment of the present invention, and the description is as follows.

[0019] Referring to FIG. 1a, a trench-type element isolation film 2 defining its active region is formed on a semiconductor substrate 1 at an appropriate place by a known STI (Shallow Trench Isolation) process. Next, in order to adjust the threshold voltage (Vt) of the cell transistor, a predetermined impurity such as boron is ion-implanted into the active region of the semiconductor substrate 1 . At this time, the ion implantation for the adjustment of the threshold voltage is preferably performed within a range of 0 to 90% of the concentration of all dopants necessary for the adjustment of the threshold voltage. Symbol 3 in t...