Active solid-state devices (e.g. – transistors – solid-state diode – Regenerative type switching device – Bidirectional rectifier with control electrode
Reexamination Certificate
1998-05-19
2001-06-26
Lee, Eddie C. (Department: 2815)
Active solid-state devices (e.g., transistors, solid-state diode
Regenerative type switching device
Bidirectional rectifier with control electrode
C257S126000, C257S500000, C257S504000, C257S544000, C257S524000, C257S547000, C257S173000, C257S154000
Reexamination Certificate
active
06252257
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to semiconductor power components, that is, components capable of switching high currents and/or having high breakdown voltages.
2. Discussion of the Related Art
Conventionally, power and/or high voltage components were realized in the form of discreet components. Eventually, to ensure the lateral isolation of these components and improve their breakdown voltage, the periphery of the components was formed of an isolating wall formed by deep diffusion of doping atoms from the upper and lower surfaces of a silicon wafer, with a cut being formed in the middle of this isolating wall.
The evolution of techniques has led to manufacturing several power components and especially several vertical components in the same chip. Examples of such structures are described in particular in European patent application EP-A-0721218 which is incorporated herein by reference. In this patent application, as in all descriptions of components formed in wells separated from one another by isolating walls, it is assumed that each of the components formed in a well surrounded by an isolating wall is properly isolated from the adjacent components which do not influence one another.
The applicant has noted that in some structures including several components formed in distinct wells separated by isolating walls, significant current flow can cause parasitic effects on an adjacent component.
SUMMARY OF THE INVENTION
The present invention is based on an analysis of this problem and of its causes and provides means for solving it.
More specifically, the present invention provides an isolating wall structure which has a doping level higher than 10
16
atoms/cm
3
at the level of its median portion, at the meeting point of deep diffusions formed from the upper and lower surfaces.
Further, the present invention provides that, preferably, the median portion of the isolating wall has a lateral extent higher than the half-thickness of the wafer in which the deep diffusions are formed.
More specifically, the present invention provides an isolating wall structure for separating elementary components formed in different wells, a component located in at least one of the wells being capable of operating with a high current density, in which the isolating wall exhibits in its median portion a concentration of carriers higher than 10
16
atoms/cm
3
.
According to an embodiment of the present invention, the width of the openings from which the dopant diffusions are formed in the upper and lower surfaces of the substrate is higher than 1.3 times the half-thickness of the substrate.
The present invention applies to forming a separation between two wells containing vertical triacs.
The present invention applies to separating two wells, one at least of which includes a diode, a thyristor or a vertical triac.
According to an embodiment of the present invention, the various components are of vertical type and the semiconductive chip includes a single rear surface metallization.
The foregoing objects, features and advantages of the present invention, will be discussed in detail in the following non-limiting description of specific embodiments in connection with the accompanying drawings.
REFERENCES:
patent: 4063966 (1977-12-01), Anthony et al.
patent: 4943835 (1990-07-01), Yakushiji et al.
patent: 5218224 (1993-06-01), Taguchi
patent: 5401984 (1995-03-01), Byatt et al.
patent: 5828089 (1998-10-01), Bernier
patent: 0721218 (1996-07-01), None
patent: 0 721 218 (1996-07-01), None
Tsutomu Yatsuo et al.: “A Diode Integrated Hishg speed Thyristor” Journal of the Japan Society of Applied Physics 1971 Supplement, vol. 40, Oct. 1971, Tokyo, pp 99-104, Oct 1971.*
French Search Report from French Patent Application No. 97 06822, filed May 28, 1997.
Tsutomu Yatsuo, et al.: “A Diode Integrated High Speed Thyristor” Journal Of The Japan Society Of Applied Physics 1971 Supplement, vol. 40, Oct. 1971, Tokyo, pp 99-104.
Duclos Franck
Rami Fabien
Galanthay Theodore E.
Lee Eddie C.
Morris James H.
SGS-Thomson Microelectronics S.A.
Warren Matthew E.
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