Method of minimizing field stop insulated gate bipolar transistor (IGBT) buffer and emitter charge variation
AssigneeAlpha and Omega Semiconductor Incorporated
InventorsMadhur Bobde, Anup Bhalla, Lingpeng Guan
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Abstract
This invention discloses an insulated gate bipolar transistor (IGBT) formed in a semiconductor substrate. The IGBT comprises a buffer layer of a first conductivity type formed below an epitaxial layer of the first conductivity having body and source regions therein. The IGBT further includes a lowly doped substrate layer below the buffer layer and a dopant layer of a second conductivity type disposed below the lowly doped substrate layer and above a drain electrode of said IGBT attached to a bottom surface of said semiconductor substrate wherein the dopant layer of the second conductivity type has a higher dopant concentration than the lowly doped substrate layer.
Claims10
A method for manufacturing a vertical insulated gate bipolar transistor (IGBT) comprising:
- growing a first epitaxial layer of a first conductivity type over a lowly doped semiconductor substrate;
- growing a second epitaxial layer of the first conductivity type over the first epitaxial layer;
- and
- annealing and processing the semiconductor to prepare the first epitaxial layer serves as a buffer layer for the IGBT having a precisely controlled amount of layer charges.
Dependencies are inferred from the claim text.