PURPOSE: To enhance a pinch-off characteristic by changing the thickness of an active layer from a source to a drain while an ion-implantation voltage is changed gradually.
CONSTITUTION: An active layer 1 is formed on a high-resistance substrate 2 by implanting an ion by using, e.g., a focused ion beam implantation method. During this process, while all implantation voltage is changed gradually, the thickness of the active layer 1 is increased from the side of a source (S) to the side of a drain (D) on the side coming into contact with the high-resistance substrate 2. After the active layer 1 is shaped in this manner, a drain voltage Vds is impressed between the source (S) and the drain (D) and a gate voltage Vg is impressed between the source (S) and a gate (G); then, a depletion layer 3 comes into face contact with the interface between the active layer 1 and the high-resistance substrate 2 during a pinch-off. Accordingly, the pinch-off becomes sure and can suppress a leakage current.
TAKEBE TOSHIHIKO
SHIRAKAWA FUTATSU
| JPH09244969A | 1997-09-19 |