CA1070434A - Reverse switching rectifier device - Google Patents
Reverse switching rectifier deviceInfo
- Publication number
- CA1070434A CA1070434A CA268,878A CA268878A CA1070434A CA 1070434 A CA1070434 A CA 1070434A CA 268878 A CA268878 A CA 268878A CA 1070434 A CA1070434 A CA 1070434A
- Authority
- CA
- Canada
- Prior art keywords
- zone
- emitter
- base
- cathode
- triggering
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
- 239000004065 semiconductor Substances 0.000 claims abstract description 10
- 239000000463 material Substances 0.000 claims description 4
- 238000010304 firing Methods 0.000 abstract description 9
- 230000000149 penetrating effect Effects 0.000 abstract 1
- 239000002674 ointment Substances 0.000 description 7
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical group [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 2
- 230000002093 peripheral effect Effects 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 239000010703 silicon Substances 0.000 description 2
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 235000010678 Paulownia tomentosa Nutrition 0.000 description 1
- 240000002834 Paulownia tomentosa Species 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- 230000000903 blocking effect Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000000295 complement effect Effects 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000008021 deposition Effects 0.000 description 1
- 230000002349 favourable effect Effects 0.000 description 1
- 238000010438 heat treatment Methods 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- 229920001296 polysiloxane Polymers 0.000 description 1
Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/86—Types of semiconductor device ; Multistep manufacturing processes therefor controllable only by variation of the electric current supplied, or only the electric potential applied, to one or more of the electrodes carrying the current to be rectified, amplified, oscillated or switched
- H01L29/861—Diodes
- H01L29/87—Thyristor diodes, e.g. Shockley diodes, break-over diodes
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
- H01L29/66—Types of semiconductor device ; Multistep manufacturing processes therefor
- H01L29/68—Types of semiconductor device ; Multistep manufacturing processes therefor controllable by only the electric current supplied, or only the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched
- H01L29/70—Bipolar devices
- H01L29/74—Thyristor-type devices, e.g. having four-zone regenerative action
- H01L29/7428—Thyristor-type devices, e.g. having four-zone regenerative action having an amplifying gate structure, e.g. cascade (Darlington) configuration
Landscapes
- Engineering & Computer Science (AREA)
- Microelectronics & Electronic Packaging (AREA)
- Power Engineering (AREA)
- Physics & Mathematics (AREA)
- Ceramic Engineering (AREA)
- Condensed Matter Physics & Semiconductors (AREA)
- General Physics & Mathematics (AREA)
- Computer Hardware Design (AREA)
- Thyristors (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A reverse switching reftifier is described in which a PNPN semiconductor structure has a specially adapted emitter zone. The emitter zone is segmented, one segment penetrating to a deeper level in the semiconductor body than a second segment. Uniform firing 18 initiated in the deeper segment which in turn fires the remaining segments of the emitter.
A reverse switching reftifier is described in which a PNPN semiconductor structure has a specially adapted emitter zone. The emitter zone is segmented, one segment penetrating to a deeper level in the semiconductor body than a second segment. Uniform firing 18 initiated in the deeper segment which in turn fires the remaining segments of the emitter.
Description
107043~
BACKGROUND OF THE INVENTION
Field of the Invention:
The present invention pertains to semiconductor switching devices and more particularly to two terminal silicon thyristor devices or reverse switching rectifier devices, hereinafter designated RSR devices.
BRIEF DESC~IPT~ON OF THE DRAWINGS
Figure 1 is a vertical cross-sectional view of a device of the prior art;
Figure 2 is a vertical cross-sectional view of one embodiment of the present invention;
Figure 3 is a vertical cross-sectional view of a second embodiment of the present invention; and, Figure 4 is a vertical cross-sectional view of a presently preferred embodiment of the present invention.
Descri~tion of the Prior Art:
Prior art RSR device 100 has a general structural configuration shown in Figure 1 wherein a body of semiconduc-tor material in the form of a wafer 110 is doped to provide four alternate semiconductivity zones. An anode-emitter zone 112 of P-type semiconductivity extends from one major surface 111 of the wafer 110 into the semiconductor material to meet a middle zone 114 of N-t~pe semiconductivity. PN
junction 113 is formed at the interface of zones 112 and 114. Similarly, P-type base zone 116 forms PN ~unction 115 with zone 1140 Base zone 116 extends from PN junction 115 to cathode-emitter zone 118 of N-type semiconductivity where PN Junction 117 is formed. In addition, zone 116 typically extends past zone 118 to the outer portion of major surface 119.
44,939 ~07()434 A supporting anode electrode 120 is affixed to ma~or surface 111 to provide good electrical and thermal contact to zone 112 as well as to provide mechanical support for the wafer 110. Typical examples of metals used for the electrode 120 are molybdenum and tungs~en, which are pre-ferred for their favorable expansion properties.
Typically, a shorted emitter construction i5 used whereby a cathode electrode 122 is affixed to ma~or surface 119 contacting the cathode-emitter zone 118 and a peripheral portion of the base zone 116 surrounding zone 118. The electrode 122 may be provided, for example, by aluminum deposition in a known manner.
The wafer 110 has a beveled edge 125 produced in a known manner in order to optimize electrical characteristics.
Disposed on the beveled edge 125 is an lnsulating and pro-tectlve coatlng 126. The coating composltlon and manner of applicatlon ls known in the art, a high temperature curing silicone varnlsh belng an example of a sultable coatlng material.
RSR device 100 of the prior art shown in Fi~ure 1 operates as an electrlcal current swltch. Briefly des-cribed, RSR de~ice 100 blocks voltage in both directions unless the device 100 is 'tturned on" or "fired" ln whlch case it carries current in the forward dlrection as indicated by the arrow 127. When RSR device 100 is forward biased as indicated by the polarity marks + and -, it may be turned on by impressing a forward voltage pulse across electrodes 120 and 122, which pulse has a sufficiently high DV/DT to cause the device 100 to turn onO Typically device 100 will turn on w~en pulsed with a voltage of greater than 5000 volts per 44, 939 ~070434 microsecond.
It has been found that device structures of the prior art, as shown in Figure 1, do not turn on uniformly along PN ~unction 115, rather such prior art devices initially turn on in a relatively small region located under an edge of the cathode-emitter zone 118 causing hot spotting and failure of the device. An example of a typical failure mode ls illustrated in Figure 1 in whlch emission of electrons from zone 118 into zone 116 more readily occurs in the dashed region 128 causing initial conduction of current through PN ~unction 115 to pass through the relatively small area of region 128 as illustrated by path X. The very high current density along path X causes localized heating which permanently destroys the blocking capability of PN ~unction 115. Uniform firing of device 100 is illustrated by paths Y
and Z which may or may not occur with device 100 due to microvar~ations in the resistivity of standard silicon bar stock.
The present invention provides an RSR device structure which assures uniform firing ln spite of such microvariations in resistivity, thus eliminating the above-mentioned failure mode of prior art devices.
SUMM~RY OF THE INVENTION
The present invention concerns a PNPN semiconduc-tor switching device having a segmented emitter zone. One segment consists of a cathode-emitter zone and a second segment consists of a triggering-emitter zone, which zone segments are separated by a base zone. The base zone has a thick portion below the cathode-emitter zone and a thin por-3~ tion below the triggering-emitter zone.
A primary advantage of the device structure of the present invention is that it fires uniformly which prevents the hot spotting attributable to prior art devices.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Figures 2, 3 and 4 illustrate various embodiments of the present invention which are similar in many respects to prior art device 100 of Figure 1, similar parts being designated by similar numerals. Since a discussion of the similar parts is given above, the balance of the specifi-cation will be devoted to the structural differences betweenthe present invention and prior art device 100.
A device 200 of the present invention is illu-strated in Figure 2. A comparison of Figures 1 and 2 dis-closes differences in the structure of the emitter zones and associated electrodes. Prior art device 100 has a single N-type emitter zone 118 which is contacted by a single elec-trode 122, whereas device 200 has a segmented emitter and associated electrodes. Specifically, device 200 of the present invention has a ring-shaped cathode-emitter zone 230 and a circular triggering-emitter zone 232 disposed within but spaced apart from the ring of zone 230. A ring-shaped 44,939 ~070~34 cathode electrode 240 is affixed to ma~or surface 219 of the wafer 210 contacting the cathode-emitter zone 230. Although not essential to the operation of devlce 200, cathode-emitter electrode 240 preferably contacts a peripheral portion of base zone 216 thereby bridging PN ~unction 231 as shown. A clrcular triggering or gate electrode 242 is affixed to ma~or surface 219 contacting triggering-emitter zone 232. It is essential to the operaticn of device 200 that gate electrode 242 be in contact with base zone 216 thereby bridging PN ~unction 233 which interfaces zones 216 and 232.
The internal operation of device 200 will now be described insofar as it differs from the internal operation of prior art device 100, external circuitry being the same.
With a forward voltage impressed on device 200, as indicated by polarity marks + and -, flrlng will occur when the device 200 is pulsed in the same manner as prior art device 100.
However, the firing of device 200 occurs in a uniform man-ner, since emission of electrons initially occurs in the area of base zone 216 between zone 232 and zone 214. This condition is achieved since base zone 214 has a thlckness separating cathode-emitter zone 230 from middle zone 214 which exceeds the thickness of the portion of base zone 216 separating triggering-emitter zone 232 from middle zone 214.
Specifically, base zone 214 has a thlckness designated by T
separating zones 230 and 214, and a thickness designated by T2 separating zones 232 and 214, as shown in Figure 2.
Typically, Tl is in the range of 25 to 45 microns with about 30 microns being preferred, while T2 is in the range of 15 3o to 35 microns with about 20 microns being preferred.
44,939 ~070434 Those skilled in the art will appreciate that a greater degree Or emission will occur from zone 232 than from zone 230 due to the relative proximity of zone 232 to zone 214. With the occurrence of emission from triggering-emitter zone 232, a current designated by path A flows from zone 232 through gate electrode 242 into base zone 216 in the direction of the negative potential of the cathode electrode 240. The current of path A flows radially out-wards in a uniform fashion, thus causing uniform initial firing of cathode-emitter zone 230 to occur in a circular area along the edge of zone 230 facing gate electrode 242, as illustrated by path B. The firing spreads uniformly and rapidly outwards from path B to paths C and D, as schema-tically illustrated in Figure 2, until the device 200 is in full conduction.
The structure of the present invention is not limited to the embodiment of Figure 2, rather the invention may be practiced by other structures within the scope of the claimed sub~ect matter, as for example, those structures of 20 Figures 3 and 4.
Figure 3 depicts a device 300 of the present invention similar to device 200 o~ Figure 2 except with the emitter segments and associated electrodes transposed. De-vice 300 has a centrally-located, circular-shaped cathode-em~tter zone 330, which is surrounded by a ring-shaped triggering-emitter zone 332. A circular-shaped cathode electrode 340 is affixed to ma~or surface 319 contacting zone 330. A ring-shaped gate electrode 342 is affixed to ma~or surface 319 contacting zone 332 and bridging PN junc-tion 333 thereby contacting a portion of base zone 316. The 44,939 portion of base zone 316 contacted by gate electrode 342preferably includes about 5 mils of base zone 316 as mea-sured from the edge of zone 332 ln the direction of zone 330.
The operation of device 300 is fully analogous to the operation of device 200 with the exception that firing is initiated at the outer edge of cathode-emitter zone 330 as schematically illustrated by path B. The firing spreads uniformly and rapidly inwards from path B to paths C and D, until the device 300 is in full conduction.
Figure 4 depicts a presently preferred device embodiment 400 similar to the embodlments of Figures 2 and 3 except that firing is caused to spread both inwards and outwards. Device 400 has a ring-shaped triggering-emitter zone 432, a clrcular cathode-emitter zone 430 disposed wlthin zone 432, and a ring-shaped cathode-emitter zone 434 surrounding zone 432. A circular-shaped cathode electrode 440 is affixed to ma~or surface 419 contacting zone 430. A
righ-shaped gate electrode 442 is affixed to ma~or surface 419 contacting zone 432 and bridging PN ~unction 433 thereby contacting a portion of base zone 416, which portion includes at least 2 mils of base zone 416 on all sides of zone 432, 5 mils being pre~erred. A ring-shaped cathode electrode 444 is affixed to ma~or surface 419 contacting zone 434, as shown. Electrodes 440 and 444 are electrically connected in common by external circuit means as schematically illustrated in Figure 4. Interfacing P-type base zone 416 with N-type emitter zones 430, 432 and 434 are PN ~unctions 431, 433 and 435, respectively.
The operation of device 400 is fully analogous to 44,939 ~07043~
the operation of devices 200 and 300 with the exception that firlng is initiated at the outer edges of zone 430 and the inner edges of zone 434 as illustrated schematically by the paths B.
It will be apparent to those skilled in the art that a varlety of structures are contemplated by the present invention and are within the scope of the appended claims, device structures 200, 300 and 400 representing a several preferred embodiments. For example, more complex arrange-ments of the N-type emitter zones, such as the so-called "interdigitated" arrangements known in the thyristor art, may be incorporated with the teachings of the present inven-tion. It will be further apparent that a complementary device may be produced by interchanging the P and N regions of the above-described device embodlments.
BACKGROUND OF THE INVENTION
Field of the Invention:
The present invention pertains to semiconductor switching devices and more particularly to two terminal silicon thyristor devices or reverse switching rectifier devices, hereinafter designated RSR devices.
BRIEF DESC~IPT~ON OF THE DRAWINGS
Figure 1 is a vertical cross-sectional view of a device of the prior art;
Figure 2 is a vertical cross-sectional view of one embodiment of the present invention;
Figure 3 is a vertical cross-sectional view of a second embodiment of the present invention; and, Figure 4 is a vertical cross-sectional view of a presently preferred embodiment of the present invention.
Descri~tion of the Prior Art:
Prior art RSR device 100 has a general structural configuration shown in Figure 1 wherein a body of semiconduc-tor material in the form of a wafer 110 is doped to provide four alternate semiconductivity zones. An anode-emitter zone 112 of P-type semiconductivity extends from one major surface 111 of the wafer 110 into the semiconductor material to meet a middle zone 114 of N-t~pe semiconductivity. PN
junction 113 is formed at the interface of zones 112 and 114. Similarly, P-type base zone 116 forms PN ~unction 115 with zone 1140 Base zone 116 extends from PN junction 115 to cathode-emitter zone 118 of N-type semiconductivity where PN Junction 117 is formed. In addition, zone 116 typically extends past zone 118 to the outer portion of major surface 119.
44,939 ~07()434 A supporting anode electrode 120 is affixed to ma~or surface 111 to provide good electrical and thermal contact to zone 112 as well as to provide mechanical support for the wafer 110. Typical examples of metals used for the electrode 120 are molybdenum and tungs~en, which are pre-ferred for their favorable expansion properties.
Typically, a shorted emitter construction i5 used whereby a cathode electrode 122 is affixed to ma~or surface 119 contacting the cathode-emitter zone 118 and a peripheral portion of the base zone 116 surrounding zone 118. The electrode 122 may be provided, for example, by aluminum deposition in a known manner.
The wafer 110 has a beveled edge 125 produced in a known manner in order to optimize electrical characteristics.
Disposed on the beveled edge 125 is an lnsulating and pro-tectlve coatlng 126. The coating composltlon and manner of applicatlon ls known in the art, a high temperature curing silicone varnlsh belng an example of a sultable coatlng material.
RSR device 100 of the prior art shown in Fi~ure 1 operates as an electrlcal current swltch. Briefly des-cribed, RSR de~ice 100 blocks voltage in both directions unless the device 100 is 'tturned on" or "fired" ln whlch case it carries current in the forward dlrection as indicated by the arrow 127. When RSR device 100 is forward biased as indicated by the polarity marks + and -, it may be turned on by impressing a forward voltage pulse across electrodes 120 and 122, which pulse has a sufficiently high DV/DT to cause the device 100 to turn onO Typically device 100 will turn on w~en pulsed with a voltage of greater than 5000 volts per 44, 939 ~070434 microsecond.
It has been found that device structures of the prior art, as shown in Figure 1, do not turn on uniformly along PN ~unction 115, rather such prior art devices initially turn on in a relatively small region located under an edge of the cathode-emitter zone 118 causing hot spotting and failure of the device. An example of a typical failure mode ls illustrated in Figure 1 in whlch emission of electrons from zone 118 into zone 116 more readily occurs in the dashed region 128 causing initial conduction of current through PN ~unction 115 to pass through the relatively small area of region 128 as illustrated by path X. The very high current density along path X causes localized heating which permanently destroys the blocking capability of PN ~unction 115. Uniform firing of device 100 is illustrated by paths Y
and Z which may or may not occur with device 100 due to microvar~ations in the resistivity of standard silicon bar stock.
The present invention provides an RSR device structure which assures uniform firing ln spite of such microvariations in resistivity, thus eliminating the above-mentioned failure mode of prior art devices.
SUMM~RY OF THE INVENTION
The present invention concerns a PNPN semiconduc-tor switching device having a segmented emitter zone. One segment consists of a cathode-emitter zone and a second segment consists of a triggering-emitter zone, which zone segments are separated by a base zone. The base zone has a thick portion below the cathode-emitter zone and a thin por-3~ tion below the triggering-emitter zone.
A primary advantage of the device structure of the present invention is that it fires uniformly which prevents the hot spotting attributable to prior art devices.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Figures 2, 3 and 4 illustrate various embodiments of the present invention which are similar in many respects to prior art device 100 of Figure 1, similar parts being designated by similar numerals. Since a discussion of the similar parts is given above, the balance of the specifi-cation will be devoted to the structural differences betweenthe present invention and prior art device 100.
A device 200 of the present invention is illu-strated in Figure 2. A comparison of Figures 1 and 2 dis-closes differences in the structure of the emitter zones and associated electrodes. Prior art device 100 has a single N-type emitter zone 118 which is contacted by a single elec-trode 122, whereas device 200 has a segmented emitter and associated electrodes. Specifically, device 200 of the present invention has a ring-shaped cathode-emitter zone 230 and a circular triggering-emitter zone 232 disposed within but spaced apart from the ring of zone 230. A ring-shaped 44,939 ~070~34 cathode electrode 240 is affixed to ma~or surface 219 of the wafer 210 contacting the cathode-emitter zone 230. Although not essential to the operation of devlce 200, cathode-emitter electrode 240 preferably contacts a peripheral portion of base zone 216 thereby bridging PN ~unction 231 as shown. A clrcular triggering or gate electrode 242 is affixed to ma~or surface 219 contacting triggering-emitter zone 232. It is essential to the operaticn of device 200 that gate electrode 242 be in contact with base zone 216 thereby bridging PN ~unction 233 which interfaces zones 216 and 232.
The internal operation of device 200 will now be described insofar as it differs from the internal operation of prior art device 100, external circuitry being the same.
With a forward voltage impressed on device 200, as indicated by polarity marks + and -, flrlng will occur when the device 200 is pulsed in the same manner as prior art device 100.
However, the firing of device 200 occurs in a uniform man-ner, since emission of electrons initially occurs in the area of base zone 216 between zone 232 and zone 214. This condition is achieved since base zone 214 has a thlckness separating cathode-emitter zone 230 from middle zone 214 which exceeds the thickness of the portion of base zone 216 separating triggering-emitter zone 232 from middle zone 214.
Specifically, base zone 214 has a thlckness designated by T
separating zones 230 and 214, and a thickness designated by T2 separating zones 232 and 214, as shown in Figure 2.
Typically, Tl is in the range of 25 to 45 microns with about 30 microns being preferred, while T2 is in the range of 15 3o to 35 microns with about 20 microns being preferred.
44,939 ~070434 Those skilled in the art will appreciate that a greater degree Or emission will occur from zone 232 than from zone 230 due to the relative proximity of zone 232 to zone 214. With the occurrence of emission from triggering-emitter zone 232, a current designated by path A flows from zone 232 through gate electrode 242 into base zone 216 in the direction of the negative potential of the cathode electrode 240. The current of path A flows radially out-wards in a uniform fashion, thus causing uniform initial firing of cathode-emitter zone 230 to occur in a circular area along the edge of zone 230 facing gate electrode 242, as illustrated by path B. The firing spreads uniformly and rapidly outwards from path B to paths C and D, as schema-tically illustrated in Figure 2, until the device 200 is in full conduction.
The structure of the present invention is not limited to the embodiment of Figure 2, rather the invention may be practiced by other structures within the scope of the claimed sub~ect matter, as for example, those structures of 20 Figures 3 and 4.
Figure 3 depicts a device 300 of the present invention similar to device 200 o~ Figure 2 except with the emitter segments and associated electrodes transposed. De-vice 300 has a centrally-located, circular-shaped cathode-em~tter zone 330, which is surrounded by a ring-shaped triggering-emitter zone 332. A circular-shaped cathode electrode 340 is affixed to ma~or surface 319 contacting zone 330. A ring-shaped gate electrode 342 is affixed to ma~or surface 319 contacting zone 332 and bridging PN junc-tion 333 thereby contacting a portion of base zone 316. The 44,939 portion of base zone 316 contacted by gate electrode 342preferably includes about 5 mils of base zone 316 as mea-sured from the edge of zone 332 ln the direction of zone 330.
The operation of device 300 is fully analogous to the operation of device 200 with the exception that firing is initiated at the outer edge of cathode-emitter zone 330 as schematically illustrated by path B. The firing spreads uniformly and rapidly inwards from path B to paths C and D, until the device 300 is in full conduction.
Figure 4 depicts a presently preferred device embodiment 400 similar to the embodlments of Figures 2 and 3 except that firing is caused to spread both inwards and outwards. Device 400 has a ring-shaped triggering-emitter zone 432, a clrcular cathode-emitter zone 430 disposed wlthin zone 432, and a ring-shaped cathode-emitter zone 434 surrounding zone 432. A circular-shaped cathode electrode 440 is affixed to ma~or surface 419 contacting zone 430. A
righ-shaped gate electrode 442 is affixed to ma~or surface 419 contacting zone 432 and bridging PN ~unction 433 thereby contacting a portion of base zone 416, which portion includes at least 2 mils of base zone 416 on all sides of zone 432, 5 mils being pre~erred. A ring-shaped cathode electrode 444 is affixed to ma~or surface 419 contacting zone 434, as shown. Electrodes 440 and 444 are electrically connected in common by external circuit means as schematically illustrated in Figure 4. Interfacing P-type base zone 416 with N-type emitter zones 430, 432 and 434 are PN ~unctions 431, 433 and 435, respectively.
The operation of device 400 is fully analogous to 44,939 ~07043~
the operation of devices 200 and 300 with the exception that firlng is initiated at the outer edges of zone 430 and the inner edges of zone 434 as illustrated schematically by the paths B.
It will be apparent to those skilled in the art that a varlety of structures are contemplated by the present invention and are within the scope of the appended claims, device structures 200, 300 and 400 representing a several preferred embodiments. For example, more complex arrange-ments of the N-type emitter zones, such as the so-called "interdigitated" arrangements known in the thyristor art, may be incorporated with the teachings of the present inven-tion. It will be further apparent that a complementary device may be produced by interchanging the P and N regions of the above-described device embodlments.
Claims (6)
1. A semiconductor switching device comprising:
a body of semiconductor material having first and second major surfaces; said body comprising a base zone of a first type of semiconductivity, a cathode-emitter zone of a second type of semiconductivity disposed adjacent to said first major surface and to said base zone to form a PN junction therewith, a triggering-emitter zone of said second type of semiconductivity extending to a deeper level into the body to be thicker than said cathode-emitter zone disposed adjacent to said first major surface and to said base zone, forming a PN junction with said base zone, and spaced apart from said cathode-emitter zone by a first portion of said base zone adjacent said first major surface, a middle zone of second type of semiconductivity disposed adjacent to said base zone forming a PN junction therewith and spaced apart from said cathode-emitter zone by a second portion of said base zone, said middle zone being spaced apart from said triggering-emitter zone by a third portion of said base zone, said second portion of said base zone being thicker than said third portion of said base zone, and an anode-emitter zone of said first type semiconductivity disposed in said body adjacent to said second major surface and to said middle zone forming a PN junction therewith;
means for electrically connecting said triggering emitter zone to said second portion of said base zone; and, means for making external electrical connections to said semiconductor switching device at said cathode-emitter and anode-emitter zones.
a body of semiconductor material having first and second major surfaces; said body comprising a base zone of a first type of semiconductivity, a cathode-emitter zone of a second type of semiconductivity disposed adjacent to said first major surface and to said base zone to form a PN junction therewith, a triggering-emitter zone of said second type of semiconductivity extending to a deeper level into the body to be thicker than said cathode-emitter zone disposed adjacent to said first major surface and to said base zone, forming a PN junction with said base zone, and spaced apart from said cathode-emitter zone by a first portion of said base zone adjacent said first major surface, a middle zone of second type of semiconductivity disposed adjacent to said base zone forming a PN junction therewith and spaced apart from said cathode-emitter zone by a second portion of said base zone, said middle zone being spaced apart from said triggering-emitter zone by a third portion of said base zone, said second portion of said base zone being thicker than said third portion of said base zone, and an anode-emitter zone of said first type semiconductivity disposed in said body adjacent to said second major surface and to said middle zone forming a PN junction therewith;
means for electrically connecting said triggering emitter zone to said second portion of said base zone; and, means for making external electrical connections to said semiconductor switching device at said cathode-emitter and anode-emitter zones.
2. A semiconductor switching device as claimed in claim 1 wherein the thickness of said second portion of said base zone is in a range from about 25 to about 45 microns, and the thickness of said third portion of said base zone is in a range from about 15 to about 35 microns.
3. The device of claim 2 wherein the thickness of said second portion of said base zone is about 30 microns and, the thickness of said third portion of said base zone is about 20 microns.
4. The device of claim 1 wherein a gate electrode bridges said PN junction between said triggering-emitter zone and said base zone on a side of said triggering-emitter zone facing said cathode-emitter zone.
5. The device of claim 4 wherein said gate electrode extends at least 2 mils away from said PN junction between said triggering-emitter zone and said base zone in a direction away from said triggering-emitter zone toward said cathode-emitter zone.
6. The device of claim 4 wherein said gate electrode extends about 5 mils away from said PN junction between said triggering-emitter zone and said base zone in a direction away from said triggering-emitter zone toward said cathode-emitter zone.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US65130376A | 1976-01-22 | 1976-01-22 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1070434A true CA1070434A (en) | 1980-01-22 |
Family
ID=24612347
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA268,878A Expired CA1070434A (en) | 1976-01-22 | 1976-12-29 | Reverse switching rectifier device |
Country Status (6)
| Country | Link |
|---|---|
| BE (1) | BE850349A (en) |
| CA (1) | CA1070434A (en) |
| DE (1) | DE2701991A1 (en) |
| FR (1) | FR2339256A1 (en) |
| GB (1) | GB1568526A (en) |
| IN (1) | IN144812B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| SE8306663L (en) * | 1982-12-08 | 1984-06-09 | Int Rectifier Corp | PROCEDURE FOR MANUFACTURING THE SEMICONDUCTOR DEVICE |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1639459A1 (en) * | 1968-03-16 | 1971-04-01 | Tokyo Shibaura Electric Co | Semiconductor-controlled rectifier device with improved turn-on properties; a method for manufacturing such a rectifier device |
| US3688164A (en) * | 1969-10-01 | 1972-08-29 | Hitachi Ltd | Multi-layer-type switch device |
| SE378479B (en) * | 1973-12-05 | 1975-09-01 | Asea Ab | |
| US4080620A (en) * | 1975-11-17 | 1978-03-21 | Westinghouse Electric Corporation | Reverse switching rectifier and method for making same |
-
1976
- 1976-12-24 IN IN2259/CAL/1976A patent/IN144812B/en unknown
- 1976-12-29 CA CA268,878A patent/CA1070434A/en not_active Expired
-
1977
- 1977-01-12 GB GB1099/77A patent/GB1568526A/en not_active Expired
- 1977-01-13 BE BE174052A patent/BE850349A/en unknown
- 1977-01-17 FR FR7701236A patent/FR2339256A1/en not_active Withdrawn
- 1977-01-19 DE DE19772701991 patent/DE2701991A1/en not_active Withdrawn
Also Published As
| Publication number | Publication date |
|---|---|
| GB1568526A (en) | 1980-05-29 |
| IN144812B (en) | 1978-07-15 |
| FR2339256A1 (en) | 1977-08-19 |
| BE850349A (en) | 1977-07-13 |
| DE2701991A1 (en) | 1977-07-28 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |