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US RE45,449 E1Granted
Power semiconductor having a lightly doped drift and buffer layer
AssigneeInfineon Technologies AG
InventorsMarkus Zundel, Franz Hirler, Armin Willmeroth
Life of this patent
Estimating the term…
Abstract
A power semiconductor element having a lightly doped drift and buffer layer is disclosed. One embodiment has, underneath and between deep well regions of a first conductivity type, a lightly doped drift and buffer layer of a second conductivity type. The drift and buffer layer has a minimum vertical extension between a drain contact layer on the adjacent surface of a semiconductor substrate and the bottom of the deepest well region which is at least equal to a minimum lateral distance between the deep well regions. The vertical extension can also be determined such that a total amount of dopant per unit area in the drift and buffer layer is larger than a breakdown charge amount at breakdown voltage.
Claims20
A power MOS transistor of the a planar type, comprising:
- a semiconductor body having a first and a second surface,
- body regions of a first conductivity type and a first dopant concentration formed in the first surface;
- a highly doped source region of a second conductivity type having a first dopant concentration, provided at the first surface;
- a contact arrangement provided at the first surface, the contact arrangement comprising a gate electrode over an insulating layer on the first surface and a source electrode, directly over the first surface and in contact with the source region;
- at least two deep, lightly doped well regions of the first conductivity type having a second dopant concentration, and having a minimum lateral distance therebetween;
- a highly doped drain contact layer of the second conductivity type and a second dopant concentration provided in or on the second surface of the semiconductor body;
- and
- an electrode provided on the a free surface of the drain contact layer;,
- wherein underneath and between the deep well regions of the first conductivity type a lightly doped drift and buffer layer of the second conductivity type and a third dopant concentration is provided, wherein the drift and buffer layer has a minimum vertical extension between the drain contact layer and the a bottom of the a deepest well region of the deep well regions and which is at least equal to the minimum lateral distance between the deep well regions,
- wherein the minimum vertical extension of the drift and buffer layer amounts to at least twice the minimum lateral distance between the deep well regions;, and
- wherein the minimum vertical extension of the drift and buffer layer between the drain contact layer and the bottom of the deepest well region is determined such that a total amount of its dopants per unit area is larger than a breakdown charge amount.
8 more elements
A power semiconductor, comprising:
- a semiconductor body having a first and a second surface, body regions of a first conductivity type and a first dopant concentration formed in the first surface;
- a highly doped source region of a second conductivity type provided at the first surface;
- a contact arrangement provided at the first surface;
- at least two deep, lightly doped well regions of the first conductivity type having a second dopant concentration, and having a minimum lateral distance therebetween;
- a highly doped drain contact layer of the second conductivity type provided in or on the second surface of the semiconductor body;
- and
- an electrode provided on a free surface of the drain contact layer,
- wherein underneath and between the deep well regions of the first conductivity type a lightly doped drift and buffer layer of the second conductivity type and a third dopant concentration is provided,
- wherein the drift and buffer layer has a minimum vertical extension between the drain contact layer and a bottom of a deepest well region of the deep well regions and which is at least equal to the minimum lateral distance between the deep well regions,
- wherein the minimum vertical extension of the drift and buffer layer amounts to at least twice the minimum lateral distance between the deep well regions, and
- wherein the minimum vertical extension of the drift and buffer layer between the drain contact layer and the bottom of the deepest well region is determined such that a total amount of its dopants per unit area is larger than a breakdown charge amount.
8 more elements
A power MOS transistor of a trench type, comprising:
- a semiconductor body having a first and a second surface, body regions of a first conductivity type and a first dopant concentration formed in the first surface;
- a highly doped source region of a second conductivity type provided at the first surface;
- a contact arrangement which extends into the first surface;
- at least two deep, lightly doped well regions of the first conductivity type having a second dopant concentration, and having a minimum lateral distance therebetween;
- a highly doped drain contact layer of the second conductivity type provided in or on the second surface of the semiconductor body;
- and
- an electrode provided on a free surface of the drain contact layer,
- wherein underneath and between the deep well regions of the first conductivity type a lightly doped drift and buffer layer of the second conductivity type and a third dopant concentration is provided,
- wherein the drift and buffer layer has a minimum vertical extension between the drain contact layer and a bottom of a deepest well region of the deep well regions and which is at least equal to the minimum lateral distance between the deep well regions,
- wherein the minimum vertical extension of the drift and buffer layer amounts to at least twice the minimum lateral distance between the deep well regions, and
- wherein the minimum vertical extension of the drift and buffer layer between the drain contact layer and the bottom of the deepest well region is determined such that a total amount of its dopants per unit area is larger than a breakdown charge amount.
8 more elements
Dependencies are inferred from the claim text.