Overvoltage protection device
AssigneeBourns, Inc.
InventorsRussell Duane, Jeremy Paul Smith, Steven Wilton Byatt
Life of this patent
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Abstract
A semiconductor overvoltage protection device in the form of a four layer diode has first and third layers of a first conductivity semiconductor material, second and fourth layers of a second conductivity type semiconductor material and a first buried region of the first conductivity type in the third layer adjacent to the junction between the second and third layers. The buried region has a greater impurity concentration than the third layer. The first layer is penetrated by a plurality of dots of the second layer extending through the first layer and the first buried region lies wholly beneath the second layer and is laterally offset from the dots and the first layer.
Claims10
A semiconductor overvoltage protection device in the form of a four layer diode comprising:
- first and third layers of a first conductivity type semiconductor material, wherein the first layer defines a perimeter;
- second and fourth layers of a second conductivity type semiconductor material;
- and
- a first buried region of the first conductivity type in the third layer adjacent to a junction between the second and third layers, the first buried region having a greater impurity concentration than the third layer so that reverse breakdown of the junction preferentially occurs through said first buried region;
- wherein:
- said first layer is penetrated by a plurality of dots of said second layer extending through said first layer;
- and
- said first buried region lies wholly beneath said second layer and outside the perimeter defined by said first layer.
Dependencies are inferred from the claim text.