Input-output (I/O) structure with capacitively triggered thyristor for electrostatic discharge (ESD) protection
First Claim
1. An input/output structure comprising:
- microelectronic device connected in circuit between a contact pad and a reference potential;
a thyristor device for protecting the microelectronic device from electrostatic discharge, the thyristor device including;
a first terminal connected to the contact pad;
a second terminal connected to the reference potential;
a PNPN thyristor structure including a first P-region, a first N-region, a second P-region and a second N-region disposed in series between the first and second terminals; and
an electrode for inducing an electric field into one of the first N-region and the second P-region;
a capacitor connected between the first terminal and the electrode; and
a resistor connected between the second terminal and the electrode.
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Accused Products
Abstract
An input/output structure includes a microelectronic device connected in circuit between a contact pad and a reference potential, and a thyristor device for protecting the microelectronic device from electrostatic discharge. The thyristor device includes first and second terminals connected to the contact pad and to the reference potential respectively, a PNPN thyristor structure including a first P-region, a first N-region, a second P-region and a second N-region disposed in series between the first and second terminals, and an electrode for inducing an electric field into the second P-region. The induced electric field increases the number of charge carriers in the second P-region, and enables the device to be triggered at a lower voltage applied between the first and second terminals. The electrode includes an insulated gate, and can be connected to either the first or second terminal. The gate can include a thick field oxide layer, or a thin oxide layer to further reduce the triggering voltage. A differentiator including a capacitor connected between the first terminal and the electrode and a resistor connected between the second terminal and the electrode prevents false triggering during normal operation. A metal interconnection layer includes an anode section which is connected to the N-region and to the second terminal, and a cathode section which is connected to the P-region, the first terminal and the electrode, such that the cathode section laterally surrounds the anode section.
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Citations
31 Claims
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1. An input/output structure comprising:
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microelectronic device connected in circuit between a contact pad and a reference potential; a thyristor device for protecting the microelectronic device from electrostatic discharge, the thyristor device including; a first terminal connected to the contact pad; a second terminal connected to the reference potential; a PNPN thyristor structure including a first P-region, a first N-region, a second P-region and a second N-region disposed in series between the first and second terminals; and an electrode for inducing an electric field into one of the first N-region and the second P-region; a capacitor connected between the first terminal and the electrode; and a resistor connected between the second terminal and the electrode. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. An input/output structure comprising:
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a microelectronic device connected in circuit between a contact pad and a reference potential; a thyristor device for protecting the microelectronic device from electrostatic discharge, the thyristor device including; a first terminal connected to the contact pad; a second terminal connected to the reference potential; a PNPN thyristor structure including a first P-region, a first N-region, a second P-region and a second N-region disposed in series between the first and second terminals; and an electrode for inducing an electric field into one of the first N-region and the second P-region; a capacitor connected between the second terminal and the electrode; and a resistor connected between the first terminal and the electrode.
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12. An input/output structure comprising:
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a microelectronic device connected in circuit between a contact pad and a reference potential; a thyristor device for protecting the microelectronic device from electrostatic discharge, the thyristor device including; a first terminal connected to the contact pad; a second terminal connected to the reference potential; a PNPN thyristor structure including a first P-region, a first N-region, a second P-region and a second N-region disposed in series between the first and second terminals; and an electrode for inducing an electric field into one of the first N-region and the second P-region, the electrode being disposed for capacitively inducing an electric field into the second P-region; a capacitor connected between the first terminal and the electrode; and a resistor connected between the second terminal and the electrode. - View Dependent Claims (13, 14)
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15. An input/output structure comprising:
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a semiconductor substrate; a contact pad formed on the substrate; a microelectronic device which is formed on the substrate and connected in circuit between the contact pad and a reference potential; a thyristor device for protecting the microelectronic device from electrostatic discharge, the thyristor device including; a P-well formed in the substrate; an N-well formed in the substrate laterally adjacent to the P-well; a P-region formed in the N-well; a first terminal connected to the contact pad and to the P-region; an N-region formed in the P-well; a second terminal connected to the reference potential and to the N-region; first circuit means connecting the first terminal to the N-well; second circuit means connecting the second terminal to the P-well; and an electrode formed over a portion of the P-well between the N-region and the N-well for inducing an electric field into said portion; a capacitor connected between the first terminal and the electrode; and a resistor connected between the second terminal and the electrode. - View Dependent Claims (16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28)
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29. An input/output structure comprising:
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a semiconductor substrate; a contact pad formed on the substrate; a microelectronic device which is formed on the substrate and connected in circuit between the contact pad and a reference potential; and a thyristor device for protecting the microelectronic device from electrostatic discharge, the thyristor device including; a P-well formed in the substrate; an N-well formed in the substrate laterally adjacent to the P-well; a P-region formed in the N-well; a first terminal connected to the contact pad and to the P-region; an N-region formed in the P-well; a second terminal connected to the reference potential and to the N-region; first circuit means connecting the first terminal to the N-well; second circuit means connecting the second terminal to the P-well; and an electrode formed over a portion of the P-well between the N-region and the N-well for inducing an electric field into said portion; a metal interconnection layer including; an anode section connected to the N-region and to the second terminal; and a cathode section connected to the P-region, the first terminal and the electrode, in which the cathode section laterally surrounds the anode section; a capacitor connected between the first terminal and the electrode; and a resistor connected between the second terminal and the electrode, in which; the cathode section laterally surrounds the resistor. - View Dependent Claims (30, 31)
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Specification