Utilization of sacrificial material for current electrode formation
AssigneeNXP B.V.
InventorsRonald Willem Arnoud Werkman, Johannes Josephus Theodorus Marinus Donkers, Petrus Hubertus Cornelis Magnee
Life of this patent
Estimating the term…
Abstract
A process for making a transistor that includes removing a sacrificial material under a base layer that includes dopants for an intrinsic base of a transistor. After the removal of the sacrificial layer to form a cavity directly under the base layer, a semiconductor material is formed in the cavity. The semiconductor layer includes dopants for a current electrode of the transistor that is located directly under the intrinsic base of the transistor.
Claims20
A method for forming a transistor, the method comprising:
- removing sacrificial material located directly under a first semiconductor layer in a first area to form a cavity, wherein the first semiconductor layer includes conductivity dopants being of a first conductivity type, wherein the conductivity dopants of the first semiconductor layer in the first area provide conductivity dopants for an intrinsic base of a transistor in the first area, wherein at least a portion of an intrinsic base of the transistor is located in the first semiconductor layer in the first area;
- after the removing the sacrificial material, forming a second semiconductor material in the cavity, the second semiconductor material including conductivity dopants of a second conductivity type opposite the first conductivity type, wherein the conductivity dopants of the second semiconductor type of the second semiconductor material formed in the cavity provide dopants for a first current electrode of the transistor, wherein at least a portion of the first current electrode is located in the second semiconductor material formed in the cavity directly below the intrinsic base.
A method for forming a transistor, the method comprising:
- removing sacrificial material located directly under a first semiconductor layer of a wafer in a first area to form a cavity, the first semiconductor layer includes conductivity dopants being of a first conductivity type, wherein the conductivity dopants of the first semiconductor layer in the first area provide conductivity dopants for an intrinsic base of a transistor, wherein at least a portion of an intrinsic base of the transistor is located in the first semiconductor layer in the first area;
- after the removing the sacrificial material, forming a second semiconductor material in the cavity directly under the first area of the first semiconductor layer and directly over the first area of the first semiconductor layer, the second semiconductor material including conductivity dopants of a second conductivity type opposite the first conductivity type, wherein:
- the conductivity dopants of the second semiconductor type of the second semiconductor material formed in the cavity provide dopants for a first current electrode of the transistor, wherein at least a portion of the first current electrode is located in the second semiconductor material formed in a cavity directly below the intrinsic base;
- the conductivity dopants of the second semiconductor type of the second semiconductor material formed directly over the first area of first semiconductor layer provide dopants for a second current electrode of the transistor, wherein at least a portion of the second current electrode is located in the second semiconductor material formed directly over the intrinsic base.
Dependencies are inferred from the claim text.