Active solid-state devices (e.g. – transistors – solid-state diode – Regenerative type switching device – Combined with field effect transistor
Patent
1995-03-28
1997-01-07
Meier, Stephen
Active solid-state devices (e.g., transistors, solid-state diode
Regenerative type switching device
Combined with field effect transistor
257142, 257147, H01L 2974, H01L 31111
Patent
active
055919910
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to a semiconductor device and a method of manufacturing the same, and more particularly to a power semiconductor device such as a static induction (SI) thyristor, a static induction (SI) transistor and a gate turn-off (GTO) thyristor, wherein the turning on/off of current is controlled by means of a gate, and to a method of manufacturing such a power semiconductor device.
TECHNICAL BACKGROUND
FIGS. 1-3 are sectionally perspective views, respectively illustrating a structure and a manufacturing method of a conventional static induction thyristor.
The conventional static induction thyristors of this type have been manufactured as follows:
First, as shown in FIG. 1, a P.sup.+ -type gate region 314 is selectively formed in a main surface of an N.sup.- -type substrate 310 by selectively diffusing P-type impurities into the main surface. Then, as shown in FIG. 2, on the N.sup.- -type substrate 310 is formed an N.sup.- -type epitaxial layer 320 by a chemical vapor deposition. At this time, the P.sup.+ -type gate region 314 is extended in this N.sup.- -type epitaxial layer 320 due to an automatic doping.
Next, as illustrated in FIG. 3, in the lower surface of the N.sup.- -type substrate 310 is formed a P.sup.+ -type layer 312 by an impurity diffusion, and in the upper surface of the N.sup.- -type epitaxial layer 320 is formed an N.sup.+ -type layer 322 also by the impurity diffusion. Then, an anode electrode 340 is formed on the lower surface of the P.sup.+ -type layer 312, and a cathode electrode 350 is formed on the upper surface of the N.sup.+ -type layer 322.
In the thus-obtained static induction thyristor 300, the P.sup.+ -type layer 312 functions as an anode region, N.sup.+ -type layer 322 as a cathode region, both of the N.sup.- -type substrate 310 and N.sup.- -type epitaxial layer 320 function as an N-type base 360, and the P.sup.+ -type gate region 314 functions as a gate which controls an anode current flowing between the anode electrode 340 and the cathode electrode 350.
FIGS. 4-6 are sectionally perspective views, respectively illustrating a structure and a manufacturing method of a conventional GTO thyristor.
The conventional GTO thyristors of this type have been manufactured in the following manner:
First, as shown in FIG. 4, a P-type layer 416 is formed in the upper surface of an N.sup.- -type substrate 410 by an impurity diffusion, and then, a P.sup.+ -type gate region 414 is selectively formed in a main surface of the P-type layer 416 by selectively diffusing P-type impurities into the main surface.
Next, as depicted in FIG. 5, a P-type epitaxial layer 420 is formed on the P-type layer 416 by a chemical vapor deposition. At this time, the P.sup.+ -type gate region 414 is expanded into this P-type epitaxial layer 420 due to an automatic doping.
Next, as shown in FIG. 6, a P-type layer 412 is formed in the lower surface of the N.sup.- -type substrate 410 by an impurity diffusion, and an N-type layer 422 is formed in the upper surface of the P-type epitaxial layer 420 by the impurity diffusion. Then, an anode electrode 440 is formed on the lower surface of the P-type layer 412, and a cathode electrode 450 is formed on the upper surface of the N-type layer 422.
In the thus-obtained GTO thyristor 400, the P-type layer 412 and N-type layer 422 function as P-type emitter and N-type emitter, respectively, the N.sup.- -type substrate 410 functions as an N-type base, the P-type layer 416 and the P-type epitaxial layer 420 function as P-type base 460, and the P.sup.+ -type gate region 414 functions as a gate which controls an anode current flowing between the anode electrode 440 and the cathode electrode 450.
FIGS. 7 and 8 are sectionally perspective views, respectively illustrating a structure and a manufacturing method of a conventional static induction thyristor with a gate metal.
The conventional static induction thyristor with a gate metal of this type have been manufactured as follows. First, as shown in FIG. 7, a groove 526 is formed in the uppe
REFERENCES:
patent: 4611235 (1986-09-01), Bhagat
Patent Abstracts of Japan, vol. 11 No. 7 (E-469) Jan. 9, 1987 & JP-A-61 182259 (Toshiba Corp) Aug. 14, 1986, Abstract.
Meier Stephen
NGK Insulators Ltd.
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