Mitsubishi Denki Kabushiki Kaisha

Ikunori Takata

Masana Harada

Kiyoto Watabe

Masanori Inoue

Takayuki Kitamura

Toshiaki Hikichi

A semiconductor device which allows an ON-state voltage to be lower than that of a conventional device and a method of manufacturing such a device. In this semiconductor device, a gate electrode is formed to have a planar area of its region covering a first base layer larger than that of its region covering a second base layer, thereby increasing a cathode short-circuit ratio of a cathode-shorted diode equivalent to this semiconductor device. As a result, a lower voltage than conventional ON-state can be obtained.

Semiconductor device having insulated gate bipolar transistor

The present invention is directed to effectively prevent 'load short-circuit breakdown' of a power Darlington transistor. When a potential different between a base BX and emitter E at a final stage of a power Darlington transistor (20) is at a specified level of voltage determined by base-emitter forward voltage of a protective bipolar transistor (32), the protective bipolar transistor (32) turns on, and accordingly, base current I.sub.B at an initial stage of the power Darlington transistor (20) is bypassed to the emitter E at the final stage. Hence, excessive rising of collector current I.sub.C of the Darlington transistor (20) is suppressed, and 'load short-circuit breakdown' is prevented. The potential difference does not depend upon the number of stages of the Darlington transistor nor temperature, and therefore, it is facilitated for Darlington transistors of various numbers of stages to design a short-circuit protective circuit to ensure a specified bypass operation in the whole range of working temperature.

Short-circuit protective circuit and power darlington transistor module

A Darlington transistor having improved comprehensive electric characteristic and a bipolar transistor having improved high voltage characteristic are obtained. A collector resistivity .rho.N.sup.- (F) of a collector high resistivity layer (11) in a front stage side transistor chip (TF) is set to 80 5/8cm and its collector film thickness tN.sup.- (F) is set to 120 .mu.m, and a collector resistivity .rho.N.sup.- (R) of a collector high resistivity layer (13) in a rear stage side transistor chip (TR) is set to 45 .OMEGA.cm and its collector film thickness tN.sup.- (R) is set to 160 .mu.m. Since .rho.N.sup.- (F)&gt;.rho.N.sup.- (R) and tN.sup.- (F)&lt;tN.sup.- (R) are satisfied, a Darlington transistor having a good comprehensive electric characteristic can be obtained, and also, since .rho.N.sup.- (R)/tN.sup.- (R)&lt;0.6 is satisfied, a bipolar transistor having a good high voltage characteristic can be obtained (FIG. 8).

Biopolar/Darlington transistor having enhanced comprehensive electricity

Disclosed herein is such multilayer electrode structure of transistor and thyristor that a second electrode region serving as an upper layer electrode region is formed on a second semiconductor region which is an active region and an insulating film which is formed on a first electrode region serving as an underlayer electrode region, whereby the second electrode region is directly in contact with the second semiconductor region for electrical connection. According to such electrode structure, the second electrode region is also formed on the insulating film while being in stable electrical connection with the second semiconductor region even if the same is formed by vacuum deposition. Thus, it is possible to obtain a semiconductor device having multilayer structure, which can be fabricated at a low cost and is excellent in electrode forming area efficiency.

Method of making a semiconductor device having multilayer structure

Disclosed herein is such multilayer electrode structure of transistor and thyristor that a second electrode region serving as an upper layer electrode region is formed on a second semiconductor region which is an active region and an insulating film which is formed on a first electrode region serving as an underlayer electrode region, whereby the second electrode region is directly in contact with the second semiconductor region for electrical connection. According to such electrode structure, the second electrode region is also formed on the insulating film while being in stable electrical connection with the second semiconductor region even if the same is formed by vacuum deposition. Thus, it is possible to obtain a semicondutor device having multilayer structure, which can be fabricated at a low cost and is excellent in electrode forming area efficiency.

Semiconductor device having a multilayer electrode structure and method

A power transistor according to the present invention improves breakdown resistance, in a monolithic structure for connecting a first-stage transistor and a second-stage transistor in Darlington connection, by constructing the same such that no parasitic transistor is substantially formed in the area for connecting the first-stage and second-stage transistors.

Power transistor

The present invention comprises a power semiconductor device in which a bipolar transistor and a diode are formed in antiparallel in a semiconductor chip with an emitter electrode (21) on one surface of the transistor (16) serving also as an anode electrode of the diode and a collector electrode (23) on another surface of the transistor serving also as a cathode electrode of the diode. A plurality of emitter lead wires (24) of the power transistor serving also as anode lead wires of the diode are connected in the anode region of the diode. Thus, electric current is made to flow from the anode region of the diode to the cathode thereof if a short circuit occurs, so that the lead wires can be prevented from being melted by large current.

Growing community of inventors

Fukuoka, Japan

Ikunori Takata