Electrostatic discharge and passive structures integrated in a vertical gate fin-type field effect diode
Field effect diode structures utilize a junction structure that has an L-shape in cross-section (a fin extending from a planar portion). An anode is positioned at the top surface of the fin, and a cathode is positioned at the end surface of the planar portion. The perpendicularity of the fin and the planar portion cause the anode and cathode to be perpendicular to one another. A first gate insulator contacts the fin between the top surface and the planar portion. A first gate conductor contacts the first gate insulator, and the first gate insulator is between the first gate conductor and the surface of the fin. Additionally, a second gate insulator contacts the planar portion between the end surface and the fin. A second gate conductor contacts the second gate insulator, and the second gate insulator is between the second gate conductor and the surface of the planar portion.
1. A field effect diode comprising:
a junction structure having an L-shape in cross-section, said junction structure comprising a planar portion and a fin portion, said fin portion extending in a first direction from said planar portion, said planar portion extending in a second direction perpendicular to said first direction, said fin portion having a top surface distal to said planar portion in said first direction, said top surface being co-planar with said planar portion, said top surface lying in a different plane from said planar portion, said planar portion having an end surface distal to said fin portion in said second direction, said end surface being co-planar with said fin portion, and said end surface lying in a different plane from said fin portion;
an anode positioned at said top surface of said fin portion;
a cathode positioned at said end surface of said planar portion;
a first gate insulator contacting a surface of said fin portion extending in said first direction, said first gate insulator contacting said surface of said fin portion between said top surface and said planar portion;
a first gate conductor contacting said first gate insulator, said first gate insulator being positioned between said first gate conductor and said surface of said fin portion;
a second gate insulator contacting a surface of said planar portion extending in said second direction, said second gate insulator contacting said surface of said planar portion between said end surface and said fin portion; and
a second gate conductor contacting said second gate insulator, said second gate insulator being positioned between said second gate conductor and said surface of said planar portion.
2. The field effect diode in claim 1 , said junction structure comprising a plurality of p-n junctions between said anode and said cathode.
3. The field effect diode in claim 1 , said junction structure comprising:
a first temporary p-n junction between said anode and said first gate conductor;
a second temporary p-n junction between said fin portion and said second gate conductor; and
a third permanent p-n junction between said cathode and said second gate conductor.
4. The field effect diode in claim 1 , said junction structure comprising a semiconductor, said anode comprising a conductor having a first type impurity, said cathode comprising a conductor having a second type impurity, and said first type impurity having an opposite polarity from said second type impurity.
5. The field effect diode in claim 1 , said first gate conductor comprising a wrap-around gate conductor surrounding sides of said fin portion extending in said first direction, and said first gate insulator being between said sides of said fin portion and said wrap-around gate conductor.
6. The field effect diode in claim 1 , said second gate conductor comprising an electrostatic discharge protection device.
7. The field effect diode in claim 1 , said junction structure comprising a conductor between said anode and said cathode based on a voltage difference between said first gate conductor and said second gate conductor.