Reference voltage generator device

Abstract

This reference voltage generator device detects a voltage corresponding to an energy gap of a semiconductor, or a voltage of a value close thereto, or a voltage based on an energy level of a semiconductor, and generates the detected voltage as a reference voltage. The reference voltage is generated by detecting a difference of threshold voltages of first and second insulated gate field-effect transistors (IGFETs). Gate electrodes of the first and second IGFETs are formed on gate insulating films which are formed on different surface areas of an identical semiconductor substrate under substantially the same conditions. The gate electrodes of the first and second IGFETs are respectively made of two semiconductors which are selected from among a semiconductor of a first conductivity type, a semiconductor of a second conductivity type and an intrinsic semiconductor made of an identical semiconductor material, and which have Fermi energy levels of values different from each other. The channels of the first and second IGFETs have an identical conductivity type. On the basis of a self-alignment structure, at least those parts of first and second polycrystalline semiconductor regions being the gate electrodes of the first and second IGFETs which are proximate to source and drain regions are doped with the same impurity as that of the source and drain regions, and a central part of one of the first and second polycrystalline semiconductor regions is doped with an impurity of a selected one of the first conductivity type and the second conductivity type.