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US 7,126,168 B1Granted
Silicon controlled rectifier structures with reduced turn on times
AssigneeNational Semiconductor Corporation
InventorsVladislav Vashchenko, Peter J. Hopper
Life of this patent
Estimating the term…
Abstract
The turn on time of an electrostatic discharge (ESD) structure, such as a silicon controlled rectifier (SCR), a low-voltage triggering SCR (LVTSCR), and a bipolar SCR (BSCR), is reduced by turning on the structure in two steps: a first step that locally turns on the pnp and npn transistors, and a second step that, over time, fully turns on the structure.
Claims30
A silicon controlled rectifier structure comprising:
- a semiconductor region of a first conductivity type;
- a semiconductor region of a second conductivity type that contacts the semiconductor region of the first conductivity type;
- a first region of the first conductivity type that contacts the semiconductor region of the second conductivity type and is spaced apart from the semiconductor region of the first conductivity type, the first region having a first length;
- a second region of the second conductivity type that contacts the semiconductor region of the second conductivity type and is spaced apart from the semiconductor region of the first conductivity type, the second region having a second length and being spaced apart from the first region, the first and second lengths being measured along substantially parallel lines, the first length being substantially longer than the second length;
- a first isolation section that contacts the semiconductor region of the second conductivity type and the first region;
- a second isolation section that contacts the semiconductor region of the second conductivity type, the first region, and the second region, the first region lying between the first and second isolation sections;
- and
- a third isolation section that contacts the first and second isolation sections and isolates the first region from the second region.
5 more elements
A silicon controlled rectifier structure comprising:
- a semiconductor region of a first conductivity type;
- a semiconductor region of a second conductivity type that contacts the semiconductor region of the first conductivity type;
- a first region of the first conductivity type that contacts the semiconductor region of the second conductivity type and is spaced apart from the semiconductor region of the first conductivity type, the first region having a first length;
- a second region of the second conductivity type that contacts the semiconductor region of the second conductivity type and is spaced apart from the semiconductor region of the first conductivity type, the second region having a second length and being spaced apart from the first region, the first and second lengths being measured along substantially parallel lines, the first length and the second length being substantially equal;
- a first isolation section that contacts the semiconductor region of the second conductivity type and the first region;
- a second isolation section that contacts the semiconductor region of the second conductivity type, the first region, and the second region, the first region lying between the first and second isolation sections;
- a first layer of metal silicide formed on the first region;
- a second layer of metal silicide formed on the second region, the first and second layers of metal silicide being spaced apart;
- a layer of isolation material formed on the first and second layers of metal silicide;
- and
- a plurality of contacts formed through the layer of isolation material to be electrically connected to the first and second regions via the first and second layers of metal silicide, respectively, the first layer of metal silicide being connected to ten times or more contacts than the second layer of metal silicide.
8 more elements
A silicon controlled rectifier structure comprising:
- a first semiconductor region having a first conductivity type;
- a second semiconductor region having a second conductivity type, the second semiconductor region contacting the first semiconductor region;
- a first doped region of the first conductivity type that contacts the second semiconductor region, the first doped region being spaced apart from the first semiconductor region, and having a first dimension;
- a second doped region of the second conductivity type that contacts the second semiconductor region, the second doped region contacting a region of the second semiconductor region that has a lower dopant concentration than a dopant concentration of the second doped region, being spaced apart from the first semiconductor region and the first doped region, and having a second dimension, the first and second dimensions being measured along substantially parallel lines, the first dimension being substantially longer than the second dimension;
- an isolation region that contacts the second semiconductor region, the first doped region, and the second doped region, the isolation region lying between the first and second doped regions;
- and
- a third doped region of the first conductivity type that contacts the second semiconductor region and the second doped region, the third doped region being spaced apart from the first semiconductor region and the first region, and having a third dimension measured along substantially parallel lines with the first and second dimensions.
4 more elements
A silicon controlled rectifier structure comprising:
- a first semiconductor region having a first conductivity type;
- a second semiconductor region having a second conductivity type, the second semiconductor region contacting the first semiconductor region;
- a first doped region of the first conductivity type that contacts the second semiconductor region, the first doped region being spaced apart from the first semiconductor region, and having a first dimension;
- a second doped region of the second conductivity type that contacts the second semiconductor region, the second doped region being spaced apart from the first semiconductor region and the first doped region, and having a second dimension, the first and second dimensions being measured along substantially parallel lines, the first dimension being substantially longer than the second dimension;
- an isolation region that contacts the second semiconductor region, the first doped region, and the second doped region, the isolation region lying between the first and second doped regions;
- a third doped region of the first conductivity type that contacts the first semiconductor region, the third doped region being spaced apart from the second semiconductor region, the first doped region, and the second doped region, the third doped region having a third dimension measured along substantially parallel lines with the first and second dimensions, the first dimension being substantially longer than the second dimension, and shorter than the third dimension;
- and
- a fourth doped region of the second conductivity type that contacts the first semiconductor region, the fourth doped region being spaced apart from the second semiconductor region, the first doped region, the second doped region, and the third doped region.
5 more elements
Dependencies are inferred from the claim text.