MOSFET with source and drain regions - enclosed by opposite conductivity type basin layers

摘要

A MOSFET includes a charge carrier flow control transistor having a gate, formed on a semiconductor for substrate, and first and second source/drain regions of first conductivity type. First and second basins of second conductivity type are formed on opposite sides of the gate, and are spaced from one another at the substrate surface, and the first basin enclosing the first source/drain region and the second basin enclosing the second source/drain region. Prodn. of the MOSFET involves (i) forming a gate on main face of a semiconductor substrate; (ii) implanting second conductivity type impurities into the substrate surface using the gate as mask for forming the first and second basins; and (iii) implanting first conductivity type impurity ions into the substrate surface using the gate as mask to form a first source/drain region in the first basin and a second source/drain region in the second basin. ADVANTAGE - The MOSFET has high breakdown resistance, freedom from mechanical stresses, low threshold voltage and short switching time. The processes do not require a high temp. heat treatment step, can be carried out on large dia. wafers and avoid variations in device characteristics from the centre to the periphery of the substrate.