Electronic device with reduced switching oscillations
The present disclosure is directed to an electronic device including a semiconductor body having a first electrical conductivity and provided with a front side; an active area of the semiconductor body, accommodating the source and gate regions of the electronic device and configured to accommodate, in use, a conductive channel of the electronic device; and an edge region of the electronic device, surrounding the active area. The edge region accommodates at least in part: i) an edge termination region, having a second electrical conductivity opposite to the first electrical conductivity, extending into the semiconductor body at the front side; and ii) a gate connection terminal of conductive material, electrically coupled to the gate region, extending on the front side partially superimposed on the edge termination region and capacitively coupled with a portion of the semiconductor body adjacent and external to the edge termination region.
1 . An electronic device comprising:
a semiconductor body having a first electrical conductivity and a front side;
an active area of the semiconductor body, the active area including a source region, a source terminal electrically coupled to the source region, a gate region, and, in use, a conductive channel;
an edge region of the electronic device, the edge region surrounding the active area, the edge region including, at least in part:
an edge termination region having a second electrical conductivity opposite to the first electrical conductivity, the edge termination region extending into the semiconductor body at the front side;
a conductive layer on the edge termination region;
a gate connection terminal including conductive material and electrically coupled to the gate region and the conductive layer, the gate connection terminal extending on the front side and partially superimposed on the edge termination region, the gate connection terminal configured to establish, in use, a capacitive coupling with a portion of the semiconductor body adjacent and external to the edge termination region;
a first dielectric layer extending in the active area and the edge region and on the front side, the conductive layer being spaced from the edge termination region by the first dielectric layer; and
a second dielectric layer extending in the active area and the edge region and on the conducive layer and the first dielectric layer,
the gate connection terminal including a first portion on the second dielectric layer and a second portion extending through the second dielectric layer to the conductive layer,
the source terminal including a first portion on the second dielectric layer and a second portion extending through the first and second dielectric layers to the source region.
2 . The electronic device according to claim 1 , wherein the edge termination region is in electrical contact with the source region.
3 . The electronic device according to claim 1 ,
wherein the active area includes a body region having the second electrical conductivity, the source region extending inside the body region, and
wherein the edge termination region is in electrical contact with the body region and has a doping dose greater than a doping dose of the body region.
4 . The electronic device according to claim 1 , wherein the gate connection terminal is a first plate of a capacitor, the semiconductor body is a second plate of the capacitor, and the second dielectric layer is interposed between the first and the second plates of the capacitor.
5 . The electronic device according to claim 1 , wherein the second dielectric layer includes Silicon Oxide, Silicon Nitride, or Silicon Oxynitride.
6 . The electronic device according to claim 1 , wherein the second dielectric layer includes a high-k material having a value of a parameter k higher than 7.
7 . The electronic device according to claim 1 , further comprising:
a first protection ring having the second electrical conductivity and a doping value lower than a doping value of the edge termination region, the first protection ring extending into the semiconductor body at an end portion of the edge termination region.
8 . The electronic device according to claim 7 , further comprising:
a second protection ring having the second electrical conductivity and a doping value lower than a doping value of the edge termination region, the second protection ring extending into the semiconductor body at an end portion of the gate connection terminal.
9 . The electronic device according to claim 8 , further comprising:
one or more floating regions having the second electrical conductivity, the one or more floating regions extending into the semiconductor body between the first protection ring and the second protection ring.
10 . The electronic device according to claim 1 ,
wherein the edge region includes a current spread layer (CSL) extending into a portion of the semiconductor body at the front side, and
wherein the CSL has the first electrical conductivity and doping value higher than a doping value of the portion of the semiconductor body in which the CSL extends into.
11 . The electronic device according to claim 1 , further comprising:
a drain region extending at a rear side, opposite to the front side, of the semiconductor body.
12 . The electronic device according to claim 11 , wherein the portion of the semiconductor body adjacent and external to the edge termination region is in electrical contact with the drain region.
13 . The electronic device according to claim 11 , wherein the gate region defines, with portions of the semiconductor body extending below the gate region and having the first electrical conductivity, a first contribution of capacitance between the gate region and the drain region of the electronic device.
14 . The electronic device according to claim 13 , wherein the capacitive coupling defines a second contribution of the capacitance between the gate region and the drain region which is added to the first contribution.
15 . The electronic device according to claim 14 , wherein the second contribution is designed with a value such that it triggers a parasitic turn-ON (PTO) phenomenon, during a turn-OFF of the electronic device.
16 . The electronic device according to claim 1 , wherein an overlap of the edge termination region with the portion of the semiconductor body adjacent and external to the edge termination region, has a value L shield along a reference axis parallel to the front side, which meets the relationship:
(
1
.15
·
10
5
/
m
)
*
Th
diel
*
w
A
A
ε
diel
≤
L
shield
≤
{
2.3
·
10
5
/
m
}
*
Th
diel
*
w
AA
ε
diel
or
(
1
·
10
-
6
*
F
/
m
2
)
*
T
h
diel
*
w
AA
ε
diel
ε
0
≤
L
shield
≤
(
2
·
10
-
6
*
F
/
m
2
)
*
T
h
diel
⋆
w
AA
ε
diel
ε
0
where:
W AA is a maximum extension, along the reference axis, of the active area, the active area having a square shape;
ε diel is a dielectric constant of the material of the second dielectric layer; and
ε 0 is a dielectric constant of vacuum.
17 . The electronic device according to claim 1 ,
wherein the edge region includes a capacitive decoupling layer extending into the semiconductor body at the front side laterally to the edge termination region and interposed between the gate connection terminal and the portion of the semiconductor body adjacent and external to the edge termination region, and
wherein the capacitive decoupling layer is configured to deplete majority carriers having the second electrical conductivity when the electronic device is in use, and allow establishment of the capacitive coupling.
18 . The electronic device according to claim 17 , wherein the capacitive decoupling layer has a doping dose of an order of 10 16 ions/cm 3 , and extends into the semiconductor body with a thickness between 0.2 and 0.4 μm.
19 . The electronic device according to claim 1 , wherein the electronic device is a vertical conduction MOSFET.
20 . The electronic device according to claim 1 , wherein the semiconductor body includes Silicon Carbide.
21 . A device comprising:
a semiconductor body having a first electrical conductivity type;
an active region in the semiconductor body, the active region including a source region, a source terminal electrically coupled to the source region, a gate region, a body region, and a channel region;
an edge region in the semiconductor body and surrounding the active region, the channel region does not extend into the edge region and is within the active region;
an edge termination region having a second electrical conductivity type, the edge termination region extending in the active region and the edge region, the edge termination region being in electrical contact with the source region and the body region;
a first dielectric layer extending in the active region and the edge region and on the semiconductor body and the edge termination region;
a conductive layer on the first dielectric layer, the conductive layer being spaced from the edge termination region by the first dielectric layer;
a second dielectric layer extending in the active region and the edge region and on the first dielectric layer and the conductive layer; and
a gate connection terminal including a first portion on the second dielectric layer and a second portion extending through second dielectric layer to the conductive layer, the gate connection terminal being in electrical contact with the conducive layer and the gate region,
the source terminal including a first portion on the second dielectric layer and a second portion extending through the first and second dielectric layers to the source region.
22 . The device according to claim 21 , further comprising:
an implanted region having the second electrical conductivity type, the implanted region extending in the edge region and underlying the gate connection terminal.
23 . A device, comprising:
a semiconductor body having a first electrical conductivity type, the semiconductor body having an active region and an edge region that encircles the active region;
a source region in the active region;
a body region in the active region;
a gate region in the active region;
an edge termination region in the active region and the edge region, the edge termination region having a second electrical conductivity type, the edge termination region electrically coupled to the source region and the body region;
a first dielectric layer extending in the active region and the edge region and on the semiconductor body and the edge termination region;
a conductive layer on the first dielectric layer, the conductive layer being spaced from the edge termination region by the first dielectric layer;
a second dielectric layer extending in the active region and the edge region and on the first dielectric layer and the conductive layer;
a source terminal electrically coupled to the source region, the source terminal including a first portion on the second dielectric layer and a second portion extending through the first and second dielectric layers to the source region, the second portion of the source terminal positioned between the gate region and the conductive layer; and
a gate terminal electrically coupled to the conducive layer and the gate region, the gate terminal including a first portion on the second dielectric layer and a second portion extending through second dielectric layer to the conductive layer.
24 . The device according to claim 23 , wherein the edge termination region encircles the active region.