Shielded gate trench MOSFET integrated with super barrier rectifier
AssigneeNami MOS CO., LTD.
InventorFu-Yuan Hsieh
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Abstract
An integrated circuit comprising a surrounding gate transistor (SGT) MOSFET and a super barrier rectifier (SBR) is disclosed. The SBR horizontally disposed in different areas to the SGT MOSFET on single chip creates a low potential barrier for majority carrier in MOS channel, therefore has lower forward voltage and reverse leakage current than conventional Schottky Barrier Rectifier. Moreover, in some preferred embodiment, a multiple stepped oxide (MSO) structure is applied to the shielded gate structure to further reduce the on-resistance.
Claims8
An integrated circuit comprising a shielded gate trench metal oxide semiconductor transistor (SGT MOSFET) and a super barrier rectifier (SBR) horizontally disposed in two different areas on a single chip, further comprising:
- an epitaxial layer of a first conductivity type extending over a substrate of said first conductivity type, said substrate having a higher doping concentration than said epitaxial layer;
- said SGT MOSFET further comprising:
- a plurality of first type trenches formed in said epitaxial layer, each of said first type trenches being filled with a first shielded electrode and a first gate electrode, said shielded electrode being insulated from said epitaxial layer by a first insulating film, said first gate electrode being insulated from said epitaxial layer by a first gate oxide film, said first shielded electrode and said first gate electrode being insulated from each other;
- a first body region of a second conductivity type having a first source region of said first conductivity type thereon and surrounding said first gate electrode padded by said first gate oxide film;
- said SBR further comprising:
- at least one second type trench formed in parallel with said first type trenches, said second type trench being filled with said a second shielded electrode and a second gate electrode, said second shielded electrode being insulated from said epitaxial layer by a second insulating film, said second gate electrode being insulated from said epitaxial layer by a second gate oxide film, said second shielded electrode and said second gate electrode being insulated from each other;
- said second gate oxide film having a thickness less than said first gate oxide film;
- a second body region of said second conductivity type having a second source region thereon and surrounding said second gate electrode padded by said second gate oxide film;
- said first body region, said second body region, said first and second source regions and said second gate electrode being shorted to a source metal through a plurality of trenched contacts;
- and
- said second body region has a shallower junction depth and a lower doping concentration than said first body region.
Dependencies are inferred from the claim text.