From f26a0af003695085d27720118a6c77304a4bfb02 Mon Sep 17 00:00:00 2001 From: chn Date: Thu, 28 Dec 2023 18:31:00 +0800 Subject: [PATCH] add Review of Silicon Carbide Processing for Power MOSFET --- .gitattributes | 2 + ...con Carbide Processing for Power MOSFET.md | 123 ++++++++++++++++++ ...on Carbide Processing for Power MOSFET.pdf | 3 + SiC/assets/image-20231228180742974.png | 3 + SiC/assets/image-20231228180819011.png | 3 + SiC/assets/image-20231228180854148.png | 3 + SiC/assets/image-20231228180910058.png | 3 + 7 files changed, 140 insertions(+) create mode 100644 .gitattributes create mode 100644 SiC/Review of Silicon Carbide Processing for Power MOSFET.md create mode 100644 SiC/Review of Silicon Carbide Processing for Power MOSFET.pdf create mode 100644 SiC/assets/image-20231228180742974.png create mode 100644 SiC/assets/image-20231228180819011.png create mode 100644 SiC/assets/image-20231228180854148.png create mode 100644 SiC/assets/image-20231228180910058.png diff --git a/.gitattributes b/.gitattributes new file mode 100644 index 0000000..4952350 --- /dev/null +++ b/.gitattributes @@ -0,0 +1,2 @@ +*.pdf filter=lfs diff=lfs merge=lfs -text +*.png filter=lfs diff=lfs merge=lfs -text diff --git a/SiC/Review of Silicon Carbide Processing for Power MOSFET.md b/SiC/Review of Silicon Carbide Processing for Power MOSFET.md new file mode 100644 index 0000000..d976809 --- /dev/null +++ b/SiC/Review of Silicon Carbide Processing for Power MOSFET.md @@ -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 + diff --git a/SiC/Review of Silicon Carbide Processing for Power MOSFET.pdf b/SiC/Review of Silicon Carbide Processing for Power MOSFET.pdf new file mode 100644 index 0000000..cde0e5d --- /dev/null +++ b/SiC/Review of Silicon Carbide Processing for Power MOSFET.pdf @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:c70cbeeaa56a38c088882bb8a5cc967c7435b6f14381f578ffd81f3d3b2f2d54 +size 5188485 diff --git a/SiC/assets/image-20231228180742974.png b/SiC/assets/image-20231228180742974.png new file mode 100644 index 0000000..19aeed5 --- /dev/null +++ b/SiC/assets/image-20231228180742974.png @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:7831052bd3fbe6c0b0d6cc2b3be7de8ff8a3f0edbd2362c837f21a78225b4c96 +size 89833 diff --git a/SiC/assets/image-20231228180819011.png b/SiC/assets/image-20231228180819011.png new file mode 100644 index 0000000..3056ccf --- /dev/null +++ b/SiC/assets/image-20231228180819011.png @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:3457e00990df687c4c177ef14a6e2ab6a9b09e2e2b993cb51a23c31707282a63 +size 443111 diff --git a/SiC/assets/image-20231228180854148.png b/SiC/assets/image-20231228180854148.png new file mode 100644 index 0000000..afdfe0a --- /dev/null +++ b/SiC/assets/image-20231228180854148.png @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:bbd01b194264870e2c2d423e259c1103e43a19b373cad0c6714366a9ef19e1f1 +size 482888 diff --git a/SiC/assets/image-20231228180910058.png b/SiC/assets/image-20231228180910058.png new file mode 100644 index 0000000..c8f5b6c --- /dev/null +++ b/SiC/assets/image-20231228180910058.png @@ -0,0 +1,3 @@ +version https://git-lfs.github.com/spec/v1 +oid sha256:ccd2ca22776a8a9bf612d1c96eef729376a0ee02fe4a65c5240bc2847b24a911 +size 311753