TY - JOUR
TI - 600 V 4H-SiC MOSFETs Fabricated in Commercial Foundry With Reduced Gate Oxide Thickness of 27 nm to Achieve IGBT-Compatible Gate Drive of 15 V
AU - Agarwal, Aditi
AU - Han, Kijeong
AU - Baliga, B. Jayant
T2 - IEEE ELECTRON DEVICE LETTERS
AB - The measured electrical characteristics of 600 V planar-gate inversion-channel 4H-SiC power MOSFETs fabricated in a 6 inch commercial foundry with 27 nm gate oxide thickness are compared with 55 nm gate oxide devices. The High-Frequency Figures-of-Merit (HF-FOMs) of the SiC MOSFETs with 27 nm gate oxide were found to surpass that of commercially available 600 V P7 Si CoolMOS products for the first time. Statistical parametric distribution data and wafer-maps for the 27 nm devices are provided to demonstrate that excellent yield and uniformity can be achieved with the reduced gate oxide thickness. These devices can be operated at 15 V gate bias compatible with IGBT gate drivers.
DA - 2019/11//
PY - 2019/11//
DO - 10.1109/LED.2019.2942259
VL - 40
IS - 11
SP - 1792-1795
SN - 1558-0563
KW - Logic gates
KW - MOSFET
KW - Voltage measurement
KW - Capacitance
KW - Silicon carbide
KW - Electric fields
KW - Silicon
KW - 4H-SiC
KW - 600 V
KW - Cgd
KW - gate oxide
KW - inversion channel
KW - planar-gate MOSFET
KW - Qgd
KW - Ron
KW - sp
KW - silicon carbide
ER -
TY - JOUR
TI - Comprehensive Physics of Third Quadrant Characteristics for Accumulation- and Inversion-Channel 1.2-kV 4H-SiC MOSFETs
AU - Han, Kijeong
AU - Baliga, B. J.
T2 - IEEE TRANSACTIONS ON ELECTRON DEVICES
AB - Detailed physics of the third quadrant electrical characteristics of 1.2-kV rated 4H-SiC accumulation (Acc) and inversion (Inv) channel MOSFETs, based on experimentally measured data and TCAD numerical simulations, are described in this paper for the first time. The power MOSFETs with various channel lengths (0.3, 0.5, 0.8, 1.1 μm) used in this paper were fabricated in a 6-in commercial foundry. Numerical simulations verified that there are two current paths in the third quadrant: 1) through the base region and 2) through the p-n body diode. This paper demonstrates that the Acc MOSFETs have a smaller third quadrant knee voltage (V _{knee} ) of -1.2 V compared with -1.9 V for the Inv MOSFETs (at V _{g} = 0V and room temperature). Numerical simulations show that this difference is due to a smaller potential barrier for electron transport from the drain to the source in the base region for accumulation channel devices than inversion channel devices. Acc devices are shown to have a lower voltage drop in the third quadrant.
DA - 2019/9//
PY - 2019/9//
DO - 10.1109/TED.2019.2929733
VL - 66
IS - 9
SP - 3923-3928
SN - 1557-9646
KW - 4H-SiC
KW - accumulation
KW - body diode
KW - inversion
KW - MOSFET
KW - silicon carbide
KW - third quadrant
ER -
TY - JOUR
TI - Analysis and Experimental Quantification of 1.2-kV 4H-SiC Split-Gate Octagonal MOSFET
AU - Han, Kijeong
AU - Baliga, B. J.
T2 - IEEE ELECTRON DEVICE LETTERS
AB - A1.2-kV rated 4H-SiC split-gate octagonal cell MOSFET (SG-OCTFET) is proposed and successfully fabricated in a 6-in foundry for the first time. The measured results quantify the benefits of the SG-OCTFET structure: improvement in high-frequency figures of merit (HF-FOM) (R _{ON} × C _{gd} ) by 1.8×, HF-FOM (R _{ON} × Q _{gd} ) by 1.6×, and FOM (C _{iss} /C _{gd} ) by 1.6× compared with the optimized compact OCTFET design due to the reduced gate-to-drain overlap area. An important conclusion of this letter is that unlike commercially available 1.2-kV SiC power MOSFETs with linear cell topology, the 1.2-kV SG-OCTFET design can outperform commercially available 600-V Si super-junction devices.
DA - 2019/7//
PY - 2019/7//
DO - 10.1109/LED.2019.2917637
VL - 40
IS - 7
SP - 1163-1166
SN - 1558-0563
KW - Silicon carbide
KW - 4H-SiC
KW - MOSFET
KW - cell design
KW - octagonal
KW - OCTFET
KW - split-gate
KW - C-gd
KW - Q(gd)
KW - HF-FOMs
ER -
TY - JOUR
TI - Comparison of Four Cell Topologies for 1.2-kV Accumulation- and Inversion-Channel 4H-SiC MOSFETs: Analysis and Experimental Results
AU - Han, Kijeong
AU - Baliga, B. J.
T2 - IEEE TRANSACTIONS ON ELECTRON DEVICES
AB - The electrical characteristics of 1.2-kV-rated 4H-SiC accumulation (Acc) and inversion (Inv) channel MOSFETs with linear, square, hexagonal, and octagonal cell topologies fabricated using the same design rules and process flow in a 6-in foundry are compared for the first time. TCAD numerical simulations have been conducted to analyze the structures. For all the cell topologies, it was found that the Acc MOSFETs have lower specific ON-resistance ( ${R}_{ \mathrm{\scriptscriptstyle ON},\textsf {sp}}$ ) than the Inv counterparts due to higher channel mobility resulting in 1.3– $2.0\times $ smaller high-frequency figure-of-merit (HF-FOM[ ${R} _{ \mathrm{\scriptscriptstyle ON}} \times {Q}_{\textsf {gd}}$ ]), where ${Q} _{\textsf {gd}}$ is the gate-to-drain charge. It is observed that the square and hexagonal cell topologies with the same structural dimensions show similar electrical performance. When compared with the standard linear cell topology: 1) the hexagonal cell topology has $1.15\times $ better specific ON-resistance and $1.12\times $ worse HF-FOM[ $\text{R}_{ \mathrm{\scriptscriptstyle ON}} \times {Q}_{\textsf {gd}}$ ] and 2) the octagonal cell topology has $1.5\times $ worse specific ON-resistance and $1.4\times $ better HF-FOM[ $\text{R}_{ \mathrm{\scriptscriptstyle ON}} \times {Q}_{\textsf {gd}}$ ]. In addition, the octagonal cell topology has a much superior figure-of-merit (FOM[ ${C} _{\textsf {iss}}/{C} _{\textsf {rss}}$ ]), where ${C} _{\textsf {iss}}$ is the input capacitance and ${C} _{\textsf {gd}}$ is the reverse transfer capacitance.
DA - 2019/5//
PY - 2019/5//
DO - 10.1109/TED.2019.2905736
VL - 66
IS - 5
SP - 2321-2326
SN - 1557-9646
KW - 4H-SiC
KW - cell
KW - C-gd
KW - C-iss
KW - hexagonal
KW - HF-FOMs
KW - linear
KW - MOSFET
KW - octagonal
KW - Q(gd)
KW - silicon carbide (SiC)
KW - square
ER -
TY - JOUR
TI - Impact of Cell Topology on Characteristics of 600V 4H-SiC Planar MOSFETs
AU - Agarwal, Aditi
AU - Han, Kijeong
AU - Baliga, B. Jayant
T2 - IEEE ELECTRON DEVICE LETTERS
AB - This letter compares the measured electrical characteristics of 600 V planar-gate inversion-channel 4H-SiC power MOSFETs fabricated with four different cell topologies (Linear, Square, Hexagonal, and Octagonal) for the first time. The High-Frequency Figures-of-Merit (HF-FOMs) of these devices were compared with the commercially available SiC device and the Si CoolMOS product. It was found that the HF-FOMs of the 600-V SiC product and our fabricated conventional Linear cell device are much worse in comparison to the Si CoolMOS product. However, the 600 V SiC power MOSFET with comparable performance to the Si CoolMOS product could be achieved by using the Octagonal cell topology.
DA - 2019/5//
PY - 2019/5//
DO - 10.1109/LED.2019.2908078
VL - 40
IS - 5
SP - 773-776
SN - 1558-0563
KW - 4H-SiC
KW - 600 V
KW - cell topologies
KW - C-gd
KW - hexagonal layout
KW - linear layout
KW - octagonal layout
KW - planar MOSFET
KW - Q(gd)
KW - R-on,R-sp
KW - silicon carbide
KW - square layout
ER -
TY - JOUR
TI - The 1.2-kV 4H-SiC OCTFET: A New Cell Topology With Improved High-Frequency Figures-of-Merit
AU - Han, Kijeong
AU - Baliga, B. J.
T2 - IEEE ELECTRON DEVICE LETTERS
AB - A 1.2 kV rated 4H-SiC OCTFET device with octagonal-cell topology is proposed and experimentally demonstrated for the first time. The device was first optimized using TCAD numerical simulations. Devices were then successfully fabricated in a 6-inch foundry. From the measured electrical characteristics, the OCTFET is demonstrated to have 1.4x superior high frequency figures-ofmerits (HF-FOM) [R _{on} × Q _{gd} ], and 2.1× superior HF-FOM [R _{on} × C _{gd} ] compared with the conventional linear-cell MOSFET.
DA - 2019/2//
PY - 2019/2//
DO - 10.1109/LED.2018.2889221
VL - 40
IS - 2
SP - 299-302
SN - 1558-0563
KW - Silicon carbide
KW - 4H-SiC
KW - MOSFET
KW - cell
KW - ALL
KW - octagonal
KW - C-gd
KW - Q(gd)
KW - HF-FOMs
ER -