Active solid-state devices (e.g. – transistors – solid-state diode – Regenerative type switching device – Combined with field effect transistor
Reexamination Certificate
2000-07-10
2003-05-27
Lee, Eddie (Department: 2815)
Active solid-state devices (e.g., transistors, solid-state diode
Regenerative type switching device
Combined with field effect transistor
C257S147000, C257S153000, C257S161000
Reexamination Certificate
active
06570193
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a self-extinguishing thyristor having a built-in reverse conducting diode.
BACKGROUND ART
The structure of a GTO (Gate Turn off) thyristor having a built-in reverse conducting diode, i.e., a reverse conducting thyristor device is disclosed in literature such as U.S. Pat. No. 4,943,840 (EP No. 224757B1) or U.S. Pat. No. 4,791,470 (Japanese Patent Laying-Open Gazette No. 61-144065), for example.
BACKGROUND ART 1
FIG. 18
is a plan view of a reverse conducting thyristor device of background art 1. A reverse conducting diode region
101
is arranged on an inner region of a semiconductor substrate and a high-resistance region
102
and a self-extinguishing thyristor region
103
are successively formed on an outer region thereof toward the outer peripheral end of the semiconductor substrate, while part of the outermost peripheral region of the semiconductor substrate is engaged in a concave portion of end field protective rubber
104
. An external takeout gate electrode region
105
is provided on an inner portion in the self-extinguishing thyristor region
103
.
FIG. 19
is a sectional view of the reverse conducting thyristor device of the background art 1, and corresponds to a longitudinal sectional view related to the line A-A′ shown in
FIG. 18. A
cathode electrode and an anode electrode of the reverse conducting diode region
101
consisting of a P-N-N+ layer are in common with an anode electrode
106
and a cathode electrode
107
of the self-extinguishing thyristor region
103
consisting of a P-N+-N-P-N layer respectively.
PRIOR ART 2
FIG. 20
is a plan view of a reverse conducting thyristor device of prior art 2. A reverse conducting diode region
101
is arranged on the innermost region of a semiconductor substrate and a high-resistance region
102
and a self-extinguishing thyristor region
103
are successively formed on its outer side toward the outer peripheral end of this substrate, while end field protective rubber
104
is provided on the outer peripheral end of this substrate. An external takeout gate electrode region
105
is provided on an outer portion of the self-extinguishing thyristor region
103
.
FIG. 21
is a longitudinal sectional view of the reverse conducting thyristor device of the prior art 2 related to the line A-A′ in
FIG. 20. A
cathode electrode and an anode electrode of the reverse conducting diode region
101
consisting of a P-N-N+ layer are in common with an anode electrode
106
and a cathode electrode
107
of the self-extinguishing thyristor region
103
consisting of a P-N+-N-P-N layer respectively.
BACKGROUND ART 3
FIG. 22
is a plan view of a reverse conducting thyristor device of background art 3. In this background art 3, a self-extinguishing thyristor region
103
is arranged on the innermost region of a semiconductor substrate and a high-resistance region
102
and a reverse conducting diode region
101
are formed toward an outer region of the semiconductor substrate contrarily to the background and prior art 1 or 2, while the outer peripheral end of this substrate is engaged in a concave portion of end field protective rubber
104
. Further, an external takeout gate electrode
105
is provided on an outer portion of the self-extinguishing thyristor region
103
.
FIG. 23
is a longitudinal sectional view of the reverse conducting thyristor device of the background art 3 related to the line A-A′ in
FIG. 22
, and both electrodes of a cathode and an anode of the reverse conducting diode region
101
consisting of a P-N-N+ layer are in common with an anode electrode
106
and a cathode electrode
107
of the self-extinguishing thyristor region
103
consisting of a P-N+-N-P-N layer respectively.
PROBLEMS OF BACKGROUND AND PRIOR ART 1 to 3
i) When comparing loss caused in the reverse conducting diode region
101
and the self-extinguishing thyristor region
103
in a general operation, loss in recovery takes a leading part in the diode while power loss at a turn-on time and a turn-off time takes a leading part in the case of the self-extinguishing thyristor, and hence the self-extinguishing thyristor region
103
causes considerably large loss as compared with the reverse conducting diode region
101
.
In the reverse conducting thyristor device having the structure of the background and prior art 1 or 2, therefore, there is such a problem that loss caused in the self-extinguishing
94
thyristor region
103
located on the outer side of the semiconductor substrate in the general operation is large and hence heat generated by this power loss fills the end field protective rubber
104
to deteriorate the characteristics of this rubber
104
.
ii) When the external takeout gate electrode region
105
is arranged on the intermediate region of the semiconductor substrate as in the background art 1 or 3, it is necessary to form a takeout terminal portion on a sheath storing the semiconductor substrate for implementing connection of the external takeout gate electrode and the outside through this takeout terminal portion, in order to connect the external takeout gate electrode with the outside. At this time, it is necessary to provide the sheath with a takeout terminal portion having a shape projecting toward the central axis of the semiconductor substrate so that the takeout terminal portion of the sheath is not in contact with the cathode electrode
107
of the self-extinguishing thyristor region
103
in the background art 1 or so that this terminal portion is not in contact with the cathode electrode
107
of the reverse conducting diode region
101
in the case of the background art 3. In the reverse conducting thyristor device having the structure of the background art 1 or 3, therefore, there is such a problem that the structure of the sheath storing the semiconductor substrate is complicated and the sheath becomes high-priced.
Such problems (i) and (ii) are common not only in a GTO thyristor (the case where a gate terminal is lead-shaped) having a built-in reverse conducting diode but also in a device having a GCT (Gate Commutated Turn-off) thyristor whose gate terminal consists of a ring-shaped metal plate and a reverse conducting diode. The structure and the operating principle of the GCT thyristor are disclosed in Japanese Pat. Laying-Open Gazette No. 9-201039 (EPO785627A2).
DISCLOSURE OF INVENTION
The present invention has been proposed in order to solve the aforementioned problems (i) and (ii), and aims at providing a reverse conducting thyristor device, a pressure-connection type semiconductor device and a semiconductor substrate in which generated heat resulting from power loss in a self-extinguishing thyristor region will not fill end field protective rubber provided on an outer peripheral end portion of a semiconductor substrate and the structure of a sheath storing the semiconductor substrate can also be simplified at the same time.
A first aspect of the present invention comprises a semiconductor substrate, a self-extinguishing thyristor region, formed in the said semiconductor substrate, structuring a self-extinguishing thyristor comprising a gate part layer, a gate electrode region comprising an upper layer region of the same conductivity type as the said gate part layer, formed in an outer peripheral region of the said semiconductor substrate along the outer periphery of the said semiconductor substrate to enclose the said self-extinguishing thyristor region with an external takeout gate electrode formed on its surface, at least one connecting region, formed in the said semiconductor substrate, comprising a surface region of the same conductivity type as the said gate part layer and connecting the said gate part layer and the said upper layer region with each other through the said surface region, at least one isolation region, formed in the said semiconductor substrate, completely enclosed with the said self-extinguishing thyristor region, the said gate electrode region and the said connecting region, and at least one r
Koga Shinji
Morishita Kazuhiro
Satoh Katsumi
Brock II Paul E
Lee Eddie
Mitsubishi Denki & Kabushiki Kaisha
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