add Review of Silicon Carbide Processing for Power MOSFET
This commit is contained in:
commit
f26a0af003
2
.gitattributes
vendored
Normal file
2
.gitattributes
vendored
Normal file
@ -0,0 +1,2 @@
|
||||
*.pdf filter=lfs diff=lfs merge=lfs -text
|
||||
*.png filter=lfs diff=lfs merge=lfs -text
|
123
SiC/Review of Silicon Carbide Processing for Power MOSFET.md
Normal file
123
SiC/Review of Silicon Carbide Processing for Power MOSFET.md
Normal file
@ -0,0 +1,123 @@
|
||||
# Review of Silicon Carbide Processing for Power MOSFET
|
||||
|
||||
# Abstract
|
||||
|
||||
inverter 逆变器
|
||||
|
||||
# Introduction
|
||||
|
||||
Over the last 50 years,
|
||||
the advancements of power devices have been primarily due to Si-based power devices.
|
||||
However, due to limitations of the intrinsic physical properties of Si,
|
||||
devices based on Si cannot be used for future power devices.
|
||||
|
||||
Hence, SiC-based power components have been a topic for extensive research
|
||||
for high voltage/power applications for more than a decade.
|
||||
|
||||
The material cost of SiC is much lesser than that of GaN,
|
||||
and the processing lines of SiC-based devices have great compatibility with that of Si-based devices.
|
||||
|
||||
## SiC Materials Properties
|
||||
|
||||
![image-20231228180742974](assets/image-20231228180742974.png)
|
||||
|
||||
![image-20231228180819011](assets/image-20231228180819011.png)
|
||||
|
||||
6H-SiC and 4H-SiC are the most preferred polytypes, especially for device production,
|
||||
as they can make a large wafer and are also commercially available.
|
||||
For high power, high temperature, and high-frequency device applications,
|
||||
4H-SiC is the most used and established-material due to its high electron mobility,
|
||||
higher bandgap, higher critical electric field,
|
||||
and shallower ionization energy of dopant, along with the availability of the single crystalline wafer.
|
||||
In addition, 4H-SiC does not exhibit anisotropy electron mobility.
|
||||
|
||||
The intrinsic carrier concentration of the polytypes is much lower than that of the Si,
|
||||
which makes SiC a suitable candidate for high-temperature applications.
|
||||
|
||||
## SiC Power Devices
|
||||
|
||||
A semiconductor device is said to be a power device if it is used as a rectifier or a switch in power electronics.
|
||||
|
||||
Most of the SiC-based power rectifiers and power switches for high voltage applications
|
||||
are designed as vertical devices based on semi-conducting substrates.
|
||||
|
||||
The main advantages of SiC power devices over Si power devices are as follows:
|
||||
|
||||
* improved voltage capability
|
||||
* outstanding switching performance
|
||||
* positive temperature coefficient
|
||||
|
||||
|
||||
On comparing theoretical limits of SiC and GaN,
|
||||
GaN limits show a better trade-off between the breakdown voltage and on-resistance.
|
||||
However, GaN-based devices are mainly employed for high-speed lower voltage applications,
|
||||
and, due to lower thermal conductivity than SiC, SiC-based devices are preferred for high-temperature applications.
|
||||
|
||||
![image-20231228180854148](assets/image-20231228180854148.png)
|
||||
|
||||
## SiC Applications
|
||||
|
||||
Si devices are used for lower power and lower frequency applications,
|
||||
while GaN-based devices are used for lower voltage and lower power high-frequency applications
|
||||
such as data centers and consumer systems;
|
||||
SiC devices are used for higher power, higher voltage switching power applications
|
||||
such as trains, electric vehicles and their battery chargers, and industrial automation.
|
||||
|
||||
![image-20231228180910058](assets/image-20231228180910058.png)
|
||||
|
||||
# SiC Critical Step
|
||||
|
||||
SiC power devices tend to show better performance when it is used as n-channels rather than p-channels;
|
||||
to achieve even more enhanced performance,
|
||||
the device needs to be grown epitaxially on low-resistivity p-type substrates.
|
||||
|
||||
The total defects of SiC wafers are mainly intrinsic material defects and structural defects
|
||||
caused by epitaxial growth.
|
||||
These defects act as recombination centers and reduce the carrier lifetime of the thick drift region significantly.
|
||||
|
||||
... reduce these defects to a very low level of about $10^{11} \mathrm{cm^{-2}}$.
|
||||
|
||||
The supply of large-size and high-quality materials and the epitaxial growth process with low defect density
|
||||
are the keys to the commercialization of SiC devices.
|
||||
|
||||
## SiC Substrate
|
||||
|
||||
The in-situ visualization of the PVT growth process is available.
|
||||
|
||||
## SiC Epitaxy
|
||||
|
||||
$\mathrm{H_2}$ etching
|
||||
|
||||
## Ion Implant
|
||||
|
||||
Most of the diffused impurities during implantation can be ignored.
|
||||
|
||||
High temperature (~500 ℃) implantation is usually used.
|
||||
|
||||
## Oxidation
|
||||
|
||||
# SiC MOSFETs
|
||||
|
||||
## Planar and Trench MOSFETs
|
||||
|
||||
## Superjunction MOSFETs
|
||||
|
||||
# Device Reliability
|
||||
|
||||
The oxide trap charging and its activation are the two main reasons behind the instability of threshold voltage.
|
||||
|
||||
## Threshold Voltage Degradation
|
||||
|
||||
## Gate Oxide Degradation
|
||||
|
||||
## Body Diode Degradation
|
||||
|
||||
The root cause of stacking faults at forward voltage is due to the expansion of base-plane dislocations (BPD)
|
||||
during forward conduction.
|
||||
The coincident electrons and holes provide energy for the BPD
|
||||
to expand into a triangular stacking fault in the drift region.
|
||||
The extended BPD penetrates through the epitaxial layer, creating a barrier for the conduction of multiple carriers,
|
||||
resulting in reduced carrier mobility.
|
||||
|
||||
# Conclusions
|
||||
|
BIN
SiC/Review of Silicon Carbide Processing for Power MOSFET.pdf
(Stored with Git LFS)
Normal file
BIN
SiC/Review of Silicon Carbide Processing for Power MOSFET.pdf
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
SiC/assets/image-20231228180742974.png
(Stored with Git LFS)
Normal file
BIN
SiC/assets/image-20231228180742974.png
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
SiC/assets/image-20231228180819011.png
(Stored with Git LFS)
Normal file
BIN
SiC/assets/image-20231228180819011.png
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
SiC/assets/image-20231228180854148.png
(Stored with Git LFS)
Normal file
BIN
SiC/assets/image-20231228180854148.png
(Stored with Git LFS)
Normal file
Binary file not shown.
BIN
SiC/assets/image-20231228180910058.png
(Stored with Git LFS)
Normal file
BIN
SiC/assets/image-20231228180910058.png
(Stored with Git LFS)
Normal file
Binary file not shown.
Loading…
Reference in New Issue
Block a user