Hitachi, Ltd.

Hitachi Microcomputer Engineering, Ltd.

Kanji Yoh

Osamu Yamashiro

Satoshi Meguro

Koichi Nagasawa

Hisahiro Moriuchi

Kotaro Nishimura

Harumi Wakimoto

Kazutaka Narita

Takashi Sakamoto

Yoshibumi Ando

Sumiaki Takei

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.

Reference voltage generator device

A method is provided for manufacturing a reference voltage generator device which 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, but which have Fermi energy levels of values different from each other.

Method of manufacturing a reference voltage generator device

A battery checker utilizes a reference voltage generator device which 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, but which have Fermi energy levels of values different from each other.

Battery checker

An abnormal surge voltage such as frictional static electricity is often applied to the external terminals of a MOSIC. In the past, the output MOS transistor in the MOSIC during normal handling of the device frequently will have its gate insulating film broken down by the application of such an abnormal surge voltage to the drain thereof. In order to prevent the gate insulating film from being broken down, in this manner a resistor is connected between the gate of the output MOS transistor and a drive circuit for driving that output MOS transistor. This construction using a resistor is superior to the construction in which the voltage to be applied to the drain of the output MOS transistor is clamped by the use of suitable clamp means only because, with the resistor arrangement, the output characteristics of the MOSIC are not restricted.

Semiconductor integrated circuit device including a protective resistor

Growing community of inventors

Kokubunji, Japan

Kanji Yoh