Semiconductor device, method of designing the same and semiconductor integrated circuit device

摘要

In an active area surrounded with an isolation formed on a silicon substrate, a large number of unit cells are disposed in a matrix, and the unit cells together form one MOSFET. Each of the unit cells includes a ring gate electrode in the shape of a regular octagon, a drain region and a source region formed at the inside and outside of the gate electrode, respectively, two gate withdrawn wires extending from the gate electrode to areas above the isolation, a substrate contact portion in which the surface of the substrate is exposed, and contacts for electrically connecting these elements with wires. These elements such as the ring gate electrode and the gate withdrawn wires are formed so as to attain a high frequency characteristic as good as possible. Thus, in a MOSFET for use in a high frequency signal device, the high frequency characteristics such as the minimum noise figure and the maximum oscillation frequency in particular can be totally improved.