Monolithic integrated circuit of a field-effect semiconductor device and a diode

Abstract

A field-effect semiconductor device such as a HEMT or MESFET is monolithically integrated with a Schottky diode for feedback, regeneration, or protection purposes. The field-effect semiconductor device includes a main semiconductor region having formed thereon a source, a drain, and a gate between the source and the drain. Also formed on the main semiconductor region, preferably between gate and drain, is a Schottky electrode electrically coupled to the source. The Schottky electrode provides a Schottky diode in combination with the main semiconductor region. A current flow is assured from Schottky electrode to drain without interruption by a depletion region expanding from the gate.

Description

CROSS REFERENCE TO RELATED APPLICATIONS[0001]This application claims priority to Japanese Patent Application No. 2006-098514, filed Mar. 31, 2006, the disclosures of which are incorporated herein by reference in its entirety.BACKGROUND OF THE INVENTION[0002]This invention relates to monolithic integrated circuits and particularly to a monolithic composite integrated circuit of a field-effect semiconductor device and a Schottky diode. The field-effect semiconductor device may take the form of a metal-semiconductor field-effect transistor (MESFET) or high-electron-mobility transistor (HEMT) among others.[0003]The MESFET and HEMT have both been known and used extensively which are made from semiconducting nitrides. Japanese Unexamined Patent Publication No. 2005-158889 is hereby cited as dealing with these kinds of semiconductor devices.[0004]Let us more closely study the typical prior art construction of the HEMT for example. It comprises an electron transit layer of undoped GaN overl...

AI Technical Summary

Benefits of technology

[0014]Such being the construction of the integrated circuit according to the invention, a current flow is assured from the Schottky electrode to the drain without interruption by a depletion region expanding from the gate means. Thus, monolithically incorporated with the field-effect semiconductor device, the Schottky electrode will well serve feedback, regenerative, or protective purposes. The Schottky diode hardly adds to the conventional size of the field-effect semiconductor device, and the monolithic combination of this device and the Schottky diode is significantly less costly than when a discrete diode is combined with the device.

Problems solved by technology

One of the problems with the HEMT of the above familiar design, as well as with the MESFET or other comparable field-effect semiconductor devices, arose when these devices were connected to an inductive or capacitive load.

However, difficulties have been experienced in applying the parasitic diode technology of the IGFET to the HEMT, MESFET and like field-effect semiconductor devices which make use of the two-dimensional electron gas layer as the channel.

This makeshift measure is of course objectionable for the extra installation space demanded by the discrete diode and the unnecessarily high manufacturing costs required.

Another problem taken up by the instant invention in regard to the field-effect semiconductor devices under consideration is the difficulty of making them normally off.

Use of such a negative power supply made the associated circuitry unnecessary complex and expensive.

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