Altera Corporation

Chih-Ching Shih

Cheng-Hsiung Huang

Yow-Juang Bill Liu

Hugh Sungki O

Hugh Sung-Ki O

Cheng H Huang

Stephanie T Tran

Guu Lin

Jeffrey T Watt

Yowjuang William Liu

Irfan Rahim

Antonio Gallerano

Shih-Lin S Lee

Yowjuang (Bill) Liu

Yow-Juang (Bill) Liu

Chiakang Sung

Jeffrey Tyhach

Yowjuang Bill Liu

Wei-Guang Wu

Yu-Cheng Richard Gao

Yow-Juang B Lu

Billy Jow-Tai Kwong

A device for providing electrostatic discharge (ESD) protection is provided. The device includes a semiconductor substrate having a drain, a source, and a gate formed therein. The drain contains a region having a resistance that is higher than the resistance of the remainder of the drain and the source. The gate region is in contact with this higher resistance region and the source. In one embodiment, the higher resistance is lacking silicide in order to provide the higher resistance. A method of forming a device for providing ESD protection is included.

Method and device for electrostatic discharge protection

A trigger circuit is provided for a pull-down device by connecting a diode between the I/O pad and the body of the pull-down device. In one embodiment, the pull-down device is formed as a plurality of discrete transistors in a single well. The drain of each transistor is connected through a ballast resistor to the I/O pad; and the source of each transistor is connected through a ballast resistor to ground. The trigger circuit is a diode formed in a different well from that of the transistors. The cathode of the diode is connected to the I/O pad and the anode is connected to the transistor well through a center tap located between the transistors. Preferably, the transistors are NMOS transistors formed in a P-well. Advantageously, the diode is an N+/PLDD diode. Alternatively, the diode is an N+/P diode where the P region is formed by an ESD implant. In other embodiments the diode is formed in the same well as the transistors. In these embodiments, either an N+/PLDD diode or an implanted diode is formed in place of one of the transistors.

I/O ESD protection device for high performance circuits

A transistor fabricated on a semiconductor substrate includes a source and a drain in the substrate; a gate on the substrate, the gate being insulated from the substrate by gate dielectric; barrier layers covering two sides of the gate and the gate dielectric; spacers of high-k material covering the barrier layers; and nitride spacers covering the spacers of high-k material. The spacers of high-k material significantly increase the node capacitance of the transistor and therefore reduce the transistor's soft error rate.

CRAM transistors with high immunity to soft error

Integrated circuit antifuse circuitry is provided. A metal-oxide-semiconductor (MOS) transistor serves as an electrically-programmable antifuse. The antifuse transistor has source, drain, gate, and substrate terminals. The gate has an associated gate oxide. In its unprogrammed state, the gate oxide is intact and the antifuse has a relatively high resistance. During programming, the gate oxide breaks down, so in its programmed state the antifuse transistor has a relatively low resistance. The antifuse transistor can be programmed by injecting hot carriers into the substrate of the device in the vicinity of the drain. Because there are more hot carriers at the drain than at the substrate, the gate oxide is stressed asymmetrically, which enhances programming efficiency. Feedback can be used to assist in turning the antifuse transistor on to inject the hot carriers.

Electrically-programmable transistor antifuses

An ESD protection structure includes, in part, a NMOS transistor having a source and drain in a well in a substrate and a gate on the substrate with the source and drain being connected between ground and a series diode, and the gate being connected to ground. The structure further includes a diode having a cathode connected to the input pad and an anode connected to the well so that the diode is reverse-biased in the event of a positive voltage ESD event on the input pad. As a result, in a positive voltage ESD event, the avalanche effect rapidly injects current into the substrate and therefore into the base of the parasitic bipolar transistor so as to trigger the transistor into conduction and discharge the ESD pulse. Alternatively, the diode is a Zener diode and the current is generated by the Zener effect. A complementary structure provides protection against a negative ESD pulse.

ESD protection structure

Circuits, methods, and apparatus for output devices having parasitic transistors for a higher output current drive. One such MOS output device includes a parasitic bipolar transistor that assists output voltage transitions. The parasitic transistor may be inherent in the structure of the MOS device. Alternately, one or more regions, such as implanted or diffused regions, may be added to the MOS device to form or enhance the parasitic bipolar device. The parasitic transistor is turned on when during an appropriate output transition and turned off once the transition is complete. The parasitic device may be turned on by injecting current into the bulk of a pull-down device, by pulling current out of the bulk of a pull-up device, or by tying the bulk of the output device to an appropriate voltage, such as VCC for a pull-down device or ground for a pull-up device.

Output device having parasitic transistor for increased current drive

A pair of SCR devices connected in antiparallel between first and second nodes. Each SCR device comprises an NPN and a PNP bipolar transistor. Reverse-biased Zener diodes are used for triggering the NPN bipolar transistor in each SCR device when it breaks down in an ESD event. Advantageously, additional Zener diodes are provided for pre-charging the PNP transistor of each SCR device at the same time, thereby reducing the delay time for turning on the PNP bipolar transistor. In addition, the breakdown current of the Zener diodes is preferably maximized by reducing the P-well and N-well resistance of the SCRs. This is achieved by connecting external resistances between the base of each bipolar transistor and the node to which the emitter of the transistor is connected.

Fast and compact SCR ESD protection device for high-speed pins

The present invention provides an ESD device for protecting thin oxide layers in transistors or capacitors in an integrated circuit. In one embodiment, the ESD device includes a silicon-controlled rectifier (SCR), the SCR including a PNP bipolar transistor and a NPN bipolar transistor. The ESD device further includes first and second trigger devices coupled to the SCR and configured to simultaneously turn on the PNP bipolar transistor and the NPN bipolar transistor in response to an ESD pulse on the ESD device. The base of the NPN bipolar transistor is floating to allow a first external resistor to be connected between the base and emitter of the NPN bipolar transistor. A second external resistor can be connected between the base and emitter of the PNP bipolar transistor.

Fast trigger ESD device for protection of integrated circuits

Integrated circuits are provided that have sensitive circuitry such as programmable polysilicon fuses. Electrostatic discharge (ESD) protection circuitry is provided that prevents damage or undesired programming of the sensitive circuitry in the presence of an electrostatic discharge event. The electrostatic discharge protection circuitry may have a power ESD device that limits the voltage level across the sensitive circuitry to a maximum voltage and that draws current away from the sensitive circuitry when exposed to ESD signals. The electrostatic discharge protection circuitry may also have an ESD margin circuit that helps to prevent current flow through the sensitive circuitry when the maximum voltage is applied across the sensitive circuitry.

Electrostatic discharge protection circuit

Methods and apparatus are provided for decreasing soft errors and cell leakage in integrated circuit structures. The structures of the invention preferably include memory cells that utilize thin-film transistors ('TFTs') for the pull-up and pull-down transistors, and well as for the pass-gates. These TFTs preferably include features such as ion implants and a dielectric with a high dielectric constant 'K.' In addition to reducing soft errors and cell leakage, the invention preferably provides other benefits such as low cell area and scalability.

Methods and apparatus for decreasing soft errors and cell leakage in integrated circuit structures

A semiconductor device and method for electrostatic discharge protection. The semiconductor device includes a first semiconductor controlled rectifier and a second semiconductor controlled rectifier. The first semiconductor controlled rectifier includes a first semiconductor region and a second semiconductor region, and the second semiconductor controlled rectifier includes the first semiconductor region and the second semiconductor region. The first semiconductor region is associated with a first doping type, and the second semiconductor region is associated with a second doping type different from the first doping type. The second semiconductor region is located directly on an insulating layer.

Compact SCR device and method for integrated circuits

An ESD device invention comprises first and second transistors formed in a substrate, each having a source, a drain and a gate, the source and drain of the first transaction being connected between ground and an I/O pin or input, the gate of the first transistor being connected to ground and the source and drain of the second transistor being connected between the substrate of the first transistor and the I/O pin or input; first and second capacitors connected in series between ground and the I/O pin or input; and at least a third transistor connected between ground and a node between the first and second capacitors to which the gate of the second transistor is also connected.

ESD device with low trigger voltage and low leakage

An integrated circuit is disclosed comprising at least one I/O pull-down device for protecting I/O logic circuits from electrostatic discharge (ESD). The turn-on voltage of the parasitic bipolar transistor in the I/O pull-down device is lowered by forming under a portion of the lightly doped drain (LDD) region of a first conductivity type of a conventional MOS transistor a second region of a second conductivity type. A P-N junction is formed between the second region and the source/drain regions. The turn-on voltage of the parasitic bipolar transistor in the I/O pull-down device can be reduced by at least 3 volts from that of a comparable device that does not practice the invention and can be varied by varying the concentration of the dopant. A method for forming the circuit including a process for recovering the current of the I/O pull-down device and its advantages are also disclosed.

Growing community of inventors

Pleasanton, CA, United States of America

Chih-Ching Shih