News Column

Patent Issued for Apparatus for Electrostatic Discharge Protection

June 18, 2014



By a News Reporter-Staff News Editor at Journal of Engineering -- Analog Devices, Inc. (Norwood, MA) has been issued patent number 8742455, according to news reporting originating out of Alexandria, Virginia, by VerticalNews editors.

The patent's inventor is Coyne, Edward (Limerick, IE).

This patent was filed on May 11, 2011 and was published online on June 3, 2014.

From the background information supplied by the inventors, news correspondents obtained the following quote: "Embodiments of the invention relate to electronic devices, and more particularly, in one or more embodiments, to electrostatic discharge protection.

"Electronic systems can be exposed to a transient electrical event, or an electrical signal of a relatively short duration having rapidly changing voltage and high power. Transient electrical events can include, for example, electrostatic discharge (ESD) events arising from the abrupt release of charge from an object or person to an electronic system.

"Transient electrical events can destroy an integrated circuit (IC) inside an electronic system due to overvoltage conditions and high levels of power dissipation over relatively small areas of the IC. High power dissipation can increase IC temperature, and can lead to numerous problems, such as gate oxide punch-through, junction damage, metal damage, and surface charge accumulation. Moreover, transient electrical events can induce latch-up (inadvertent creation of a low-impedance path), thereby disrupting the functioning of the IC and potentially causing permanent damage to the IC from self-heating in the latch-up current path. Thus, there is a need to provide an IC with protection from such transient electrical events."

Supplementing the background information on this patent, VerticalNews reporters also obtained the inventor's summary information for this patent: "In one embodiment, an apparatus includes: an internal circuit electrically coupled between a first node and a second node; and a protection device electrically coupled between the first node and the second node. The protection device is configured to protect the internal circuit from transient electrical events. The protection device includes: a buried layer 510 having a doping of a first type; a first plug 540 overlying the buried layer, and having a doping of the first type with a higher doping concentration than that of the buried layer, the first plug having an annular shape when viewed from above from the protection device; a first well 520 overlying the buried layer, and laterally surrounded by the first plug, the first well having a doping of the first type with a lower doping concentration than that of the first plug; a second plug 530 laterally surrounding the first plug, the second plug having a doping of a second type different from the first type; a first region 550 disposed at least in an end portion of the first well 520 opposite the buried layer, and electrically coupled to the first node, the first region having a doping of the second type with a higher doping concentration than that of the second plug 530; a second region 560 disposed in a top portion of the second plug 530, and electrically coupled to the second node, the second region having a doping of the second type with a higher doping concentration than that of the second plug; and a resistor electrically coupled between the first region 550 and the first plug 540, wherein the resistor is disposed outside the first region and the first plug.

"In another embodiment, an apparatus includes: an internal circuit electrically coupled between a first node and a second node; and a protection device electrically coupled between the first node and the second node, wherein the protection device is configured to protect the internal circuit from transient electrical events. The protection device includes: a buried layer having a doping of a first type; a first plug disposed directly over the buried layer, and having a doping of the first type with a higher doping concentration than that of the buried layer, the first plug having an annular shape when viewed from above; a first well disposed directly over the buried layer, and laterally surrounded by the first plug, the first well having a doping of the first type with a lower doping concentration than that of the first plug; a second plug laterally surrounding the first plug, the second plug having a doping of a second type different from the first type; a first region disposed at least in an end portion of the first well 520 opposite the buried layer, and electrically coupled to the first node, the first region having a doping of the second type with a higher doping concentration than that of the second plug; and a second region disposed in a top portion of the second plug, and electrically coupled to the second node, the second region having a doping of the second type with a higher doping concentration than that of the second plug.

"In yet another embodiment, an apparatus includes: an internal circuit electrically coupled between a first node and a second node; and a protection device electrically coupled between the first node and the second node, wherein the protection device is configured to protect the internal circuit from transient electrical events. The protection device includes: a buried layer having a doping of a first type; a first plug overlying the buried layer, and having a doping of the first type with a higher doping concentration than that of the buried layer, the first plug having an annular shape when viewed from above; a first well overlying the buried layer, and laterally surrounded by the first plug, the first well having a doping of the first type with a lower doping concentration than that of the first plug; a second plug laterally surrounding the first plug, the second plug having a doping of a second type different from the first type; a first region disposed in a top portion of the first well and electrically coupled to the first node, the first region having a doping of the second type with a higher doping concentration than that of the second plug; a second region disposed in a top portion of the second plug, and electrically coupled to the second node, the second region having a doping of the second type with a higher doping concentration than that of the second plug; and a diode array comprising one or more diodes connected in series between the first plug and the second region.

"In yet another embodiment, an apparatus includes: an internal circuit electrically coupled between a first node and a second node; and a protection device electrically coupled between the first node and the second node, wherein the protection device is configured to protect the internal circuit from transient electrical events. The protection device includes: a buried layer having a doping of a first type; a first plug overlying the buried layer, and having a doping of the first type with a higher doping concentration than that of the buried layer, the first plug having an annular shape when viewed from above; a first well overlying the buried layer, and laterally surrounded by the first plug, the first well having a doping of the first type with a lower doping concentration than that of the first plug; a second plug laterally surrounding the first plug, the second plug having a doping of a second type different from the first type; a first region disposed in a top portion of the first well and electrically coupled to the first node, the first region having a doping of the second type with a higher doping concentration than that of the second plug, wherein the first region disposed in a top portion of the first well and at least in a portion of a top portion of the first plug; and a second region disposed in a top portion of the second plug, and electrically coupled to the second node, the second region having a doping of the second type with a higher doping concentration than that of the second plug.

"In yet another embodiment, an apparatus includes: an internal circuit electrically coupled between a first node and a second node; and a protection device electrically coupled between the first node and the second node, wherein the protection device is configured to protect the internal circuit from transient electrical events. The protection device includes: a buried layer having a doping of a first type; a first plug overlying the buried layer, and having a doping of the first type with a higher doping concentration than that of the buried layer, the first plug having an annular shape when viewed from above; a first well overlying the buried layer, and laterally surrounded by the first plug, the first well having a doping of the first type with a lower doping concentration than that of the first plug; a second plug laterally surrounding the first plug, the second plug having a doping of a second type different from the first type; a first region disposed in a top portion of the first well, the first region having a doping of the second type with a higher doping concentration than that of the second plug; and a second region disposed in a top portion of the second plug, and electrically coupled to the second node, the second region having a doping of the second type with a higher doping concentration than that of the second plug; a first resistor electrically coupled between the first region and the first node; and a second resistor electrically coupled to the first plug.

"In yet another embodiment, an apparatus includes: an internal circuit electrically coupled between a first node and a second node; and a protection device electrically coupled between the first node and the second node, wherein the protection device is configured to protect the internal circuit from transient electrical events. The protection device includes: a silicon-controlled rectifier (SCR) having an anode, a gate, and a cathode, wherein the anode is electrically coupled to the first node, and the cathode is electrically coupled to the second node; and a diode array comprising a plurality of diodes connected in series between the gate and the anode of the silicon-controlled rectifier and arranged such that the diodes conduct a current into the SCR to turn on the SCR when the diodes break down.

"In yet another embodiment, an apparatus includes: an internal circuit electrically coupled between a first node and a second node; and a protection device electrically coupled between the first node and the second node, wherein the protection device is configured to protect the internal circuit from transient electrical events. The protection device includes: a silicon-controlled rectifier (SCR) having an anode, a gate, and a cathode, wherein the anode is electrically coupled to the first node, and the cathode is electrically coupled to the second node; and a resistor electrically coupled between the gate and the cathode of the SCR.

"In yet another embodiment, an apparatus includes: an internal circuit electrically coupled between a first node and a second node; and a protection device electrically coupled between the first node and the second node, wherein the protection device is configured to protect the internal circuit from transient electrical events. The protection device includes a silicon-controlled rectifier (SCR) having an anode, a gate, and a cathode, wherein the anode is electrically coupled to the first node, and the cathode is electrically coupled to the second node. The SCR includes: a substrate having a doping of a first type; a first well disposed in a first upper portion of the substrate, and having a doping of a second type different from the first type; a second well disposed in a second upper portion of the substrate, and spaced apart laterally from the first well such that a third upper portion of the substrate is laterally interposed between the first and second wells, the second well having a doping of the second type, the third upper portion having a doping of the first type; a first region disposed in a top portion of the first well, and having a doping of the second type with a higher doping concentration than that of the first well, the first region being electrically coupled to the second node; a second region disposed in a top portion of the second well, and having a doping of the second type with a higher doping concentration than that of the second well; a third region disposed in the first well adjacent to the first region such that the third region is interposed laterally between the first region and the third upper portion of the substrate, the third region having a doping of the first type with a higher doping concentration than that of the substrate; a fourth region disposed in the second well adjacent to the second region such that the fourth region is interposed laterally between the second region and the third upper portion of the substrate, the fourth region having a doping of the first type with a higher doping concentration than that of the substrate, the fourth region being electrically coupled to the first node; and a gate contact disposed on the third upper portion of the substrate. The third region has a lateral dimension extending in a direction from the first region toward the third upper portion of the substrate, and the lateral dimension of the third region is greater than the lateral dimension of the first region in the direction.

"In yet another embodiment, an apparatus includes: an internal circuit electrically coupled between a first node and a second node; and a protection device electrically coupled between the first node and the second node, wherein the protection device is configured to protect the internal circuit from transient electrical events. The protection device includes: a silicon-controlled rectifier (SCR) having an anode, a gate, and a cathode, wherein the anode is electrically coupled to the first node; a first resistor electrically coupled between the cathode of the SCR and the second node; and a second resistor electrically coupled to the gate of the SCR.

"In yet another embodiment, an apparatus includes: an internal circuit electrically coupled between a first node and a second node; and a protection device electrically coupled between the first node and the second node, wherein the protection device is configured to protect the internal circuit from transient electrical events. The protection device includes: a bipolar device having a first terminal, a second terminal, and a third terminal, wherein the first terminal is electrically coupled to the first node, and the third terminal is electrically coupled to the second node; an impedance block electrically coupled between the second terminal of the bipolar device and a first voltage reference, wherein the impedance block is configured to have a varying impedance; and an impedance control circuit configured to vary the impedance of the impedance block."

For the URL and additional information on this patent, see: Coyne, Edward. Apparatus for Electrostatic Discharge Protection. U.S. Patent Number 8742455, filed May 11, 2011, and published online on June 3, 2014. Patent URL: http://patft.uspto.gov/netacgi/nph-Parser?Sect1=PTO1&Sect2=HITOFF&d=PALL&p=1&u=%2Fnetahtml%2FPTO%2Fsrchnum.htm&r=1&f=G&l=50&s1=8742455.PN.&OS=PN/8742455RS=PN/8742455

Keywords for this news article include: Silicon, Analog Devices Inc., Medical Device Companies.

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Source: Journal of Engineering


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