Zener zap diode structure compatible with tungsten plug technology

A zener zap device formed in a fabrication process using a tungsten plug process wherein the tungsten plug process dictates standard sized contact openings, the zener zap device comprising:

• a semiconductor layer;
• a first region of a first conductivity type formed in the semiconductor layer;
• a second region of a second conductivity type formed in the semiconductor layer;
• a dielectric layer formed overlaying the top surface of the semiconductor layer, the dielectric layer having a first enlarged contact opening and a second enlarged contact opening positioned above and exposing a portion of the first region and a portion of the second region respectively, the first and second enlarged contact openings having dimensions larger than the standard sized contact opening;
• a first metal contact formed in the first enlarged contact opening, the first metal contact comprising tungsten formed on the sidewall of the first enlarged contact opening and aluminum formed in electrical contact with the exposed surface of the first region;
• and
• a second metal contact formed in the second enlarged contact opening, the second metal contact comprising tungsten formed on the sidewall of the second enlarged contact opening and aluminum formed in electrical contact with the exposed surface of the second region.

A method for forming a zener zap diode in a fabrication process using a tungsten plug process wherein the tungsten plug process dictates standard sized contact openings, the method comprising:

• providing a semiconductor structure;
• forming a first region of a first conductivity type in the semiconductor structure;
• forming a second region of a second conductivity type in the semiconductor structure;
• forming a dielectric layer overlaying the semiconductor structure;
• forming first and second enlarged contact openings in the dielectric layer positioned above and exposing a portion of the first region and a portion of the second region respectively, the first and second enlarged contact openings having dimensions larger than the standard sized contact opening;
• forming a first metal contact in the first enlarged contact opening, the first metal contact comprising tungsten formed on the sidewall of the first enlarged contact opening and aluminum formed in electrical contact with the exposed surface of the first region;
• and
• forming a second metal contact in the second enlarged contact opening, the second metal contact comprising tungsten formed on the sidewall of the second enlarged contact opening and aluminum formed in electrical contact with the exposed surface of the second region.

A Schottky diode formed in a fabrication process using a tungsten plug process wherein the tungsten plug process dictates standard sized contact openings, the Schottky diode comprising:

• a semiconductor layer;
• a first region of a first conductivity type formed in the semiconductor layer, the first region being lightly doped;
• a second region of the first conductivity type in electrical contact with the first region, the second region being heavily doped;
• a dielectric layer formed overlaying the top surface of the semiconductor layer, the dielectric layer having a first contact opening and a second contact opening positioned above and exposing a portion of the first region and a portion of the second region respectively, the first contact opening being an enlarged contact opening having dimensions larger than the standard sized contact opening;
• a first metal contact formed in the first enlarged contact opening, the first metal contact comprising tungsten formed on the sidewall of the first enlarged contact opening and aluminum formed in electrical contact with the exposed surface of the first region;
• and
• a second metal contact formed in the second contact opening, the second metal contact comprising a tungsten plug formed in the second contact opening and aluminum formed on the top surface of the tungsten plug and in electrical contact with the tungsten plug.

A method for forming a Schottky diode in a fabrication process using a tungsten plug process wherein the tungsten plug process dictates standard sized contact openings, the method comprising:

• providing a semiconductor structure;
• forming a first region of a first conductivity type in the semiconductor structure, the first region being lightly doped;
• forming a second region of the first conductivity type in electrical contact with the first region, the second region being heavily doped;
• forming a dielectric layer overlaying the semiconductor structure;
• forming a first enlarged contact opening in the dielectric layer positioned above and exposing a portion of the first region, the first enlarged contact opening having dimensions larger than the standard sized contact opening;
• forming a second contact opening in the dielectric layer positioned above and exposing a portion of the second region, the second contact opening being the standard sized contact opening;
• forming a first metal contact in the first enlarged contact opening, the first metal contact comprising tungsten formed on the sidewall of the first enlarged contact opening and aluminum formed in electrical contact with the exposed surface of the first region;
• and
• forming a second metal contact in the second contact opening, the second metal contact comprising a tungsten plug formed in the second contact opening and aluminum formed on the top surface of the tungsten plug and in electrical contact with the tungsten plug.