Active solid-state devices (e.g. – transistors – solid-state diode – Field effect device – Having insulated electrode
Reexamination Certificate
1999-04-30
2001-05-08
Smith, Matthew (Department: 2825)
Active solid-state devices (e.g., transistors, solid-state diode
Field effect device
Having insulated electrode
Reexamination Certificate
active
06229181
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention generally relates to semiconductor devices and integrated circuits that require electrostatic discharge (hereinafter referred to as “ESD”) protection. In typical electrical circuits, such devices include Resistor-Capacitor (hereinafter referred to as “RC”) or Resistor-Capacitor-Inductor (hereinafter referred to as “RCL”) networks and fabrication methods therefor. Specifically, this invention relates to an improved semiconductor device and a method for manufacturing such an improved semiconductor device which provides protection against ESD for active or passive devices or any type of integrated circuit.
2. Description of the Related Art
In the past art, the primary method for integrating protection of ESD in RC Network types of semiconductor devices was to use or incorporate certain types of diodes, i.e. Schottky diodes and Zener diodes to provide for ESD protection. For example, Rao et al. (U.S. Pat. Nos. 5,355,014 and 5,770,886) employs a Schottky diode for ESD protection.
However, one primary disadvantage of the use of a Schottky/Zener diode technique for ESD protection is the added complexity of the process flow for manufacturing these fairly complicated semiconductor devices. The prior art semiconductor process for fabricating these types of semiconductor devices usually required an epitaxy growth process step to obtain or form regions of P type conductivity, formation of the LOCOS field isolation and formation of a multi-layer metalization system on the backside of the semiconductor wafer.
Therefore, a simpler, more cost effective and more reliable semiconductor device and semiconductor process solution was needed or required as contrasted to both the semiconductor device and process complexity incurred by the incorporation of Schottky/Zener diodes to provide ESD protection for use with, for example, RC network semiconductor devices.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved semiconductor structure and method for protecting an active or passive device against ESD.
It is another object of the present invention to provide an improved semiconductor structure and method for protecting an integrated circuit device against ESD.
It is another object of the present invention to provide an improved semiconductor structure and method for protecting an active or passive network against ESD which provides a simpler, more cost effective and more reliable solution than the prior use of a Schottky diode for ESD protection.
It is still another object of the present invention to provide an improved semiconductor structure and method for protecting an active or passive network against ESD which provides a simpler, more cost effective and more reliable solution than a Zener diode for ESD protection.
It is a further object of the present invention to provide an improved semiconductor structure for protecting an active or passive network against ESD which utilizes a simpler, more cost effective and more reliable type of semiconductor device structure which is an improved diode comprising an anode, cathode and injector.
BRIEF DESCRIPTION OF THE PREFERRED EMBODIMENT
In accordance with one embodiment of the present invention, a semiconductor diode is provided for protection of active or passive devices against electrostatic discharge comprising a P well cathode located within an N type substrate, an N+ type anode region located within the P well cathode, an N+ type injector region located within the P well cathode and spaced from the N+ type anode region, a P+ type ohmic contact region located within the P well cathode and in contact with the N+ type injector region, a first metal electrode in electrical contact with a surface portion of the N+ type anode region, and a second metal electrode in electrical contact with surface portions of both the N+ type injector region and the P+ type ohmic contact region which are adjacent and co-planar to each other. The improved diode is preferably fabricated in a single, monolithic integrated circuit made of silicon.
In accordance with another embodiment of the invention, a method is disclosed for fabricating a semiconductor device structure for protection of active or passive devices against ESD which comprises the steps of forming a P well cathode located within an N type substrate, forming an N+ type anode region located within the P well cathode, forming an N+ type injector region located within the P well cathode and spaced from the N+ type anode region, forming a P+ type ohmic contact region located within the P well cathode and in contact with the N+ type injector region, forming a first metal electrode in electrical contact with a surface portion of the N+ type anode region, and forming a second metal electrode in electrical contact with surface portions of both the N+ type injector region and the P+ type ohmic contact region which are adjacent and co-planar to each other.
The foregoing and other objects, features, and advantages of the invention will be apparent from the following, more particular, description of the preferred embodiments of the invention, as illustrated in the accompanying drawings.
REFERENCES:
patent: 4170017 (1979-10-01), Klein et al.
patent: 5227012 (1993-07-01), Brandli et al.
patent: 5355014 (1994-10-01), Rao
patent: 5468984 (1995-11-01), Efland et al.
patent: 5770886 (1998-06-01), Rao
Kravtchenko Dmitri G.
Paderin Anatoly U.
Digital Devices, Inc.
Lee Calvin
Moy Jeffrey D.
Smith Matthew
Weiss Jeffrey
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