Patent attributes
Where the silicon active layer of an SOI substrate is used as a resistor, it is difficult to form small wells densely in a semiconductor support substrate portion under the resistor because of the presence of a buried insulation film. It is also difficult to control the potential division of the wells. Therefore, there is the problem that the resistance value is varied by potential variations. Island-like silicon active layer and buried insulation film are formed by etching. Side spacers made of polycrystalline silicon are formed on the sidewalls of step portions of the island-like silicon active layer, buried insulation film, and semiconductor support substrate. The potentials at the side spacers are controlled. Thus, resistance value variations due to variations in the potential difference between the semiconductor support substrate and the resistor can be suppressed. Furthermore, accurate potential division owing to each resistor is facilitated.
