Browsing by Author "Hung, Chia-Lung"

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Failure Analysis on TiAl Metallization Process for Ohmic Contact on 4H-SiC pMOSFET
(2019-01-01)
Hung, Chia-Lung
;
Cheng, Jung-Chien
;
Tsui, Bing-Yue
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
SiC is suitable for high-power and high-temperature applications due to its' wide energy bandgap and high thermal conductivity. Most literature focus on SiC nMOSFET due to higher electron mobility than hole. In this work, we fabricated 4H-SiC pMOSFET using TiAl alloy as contact metal to reduce the contact resistivity. However, ultrahigh leakage current was measured among all terminals of the pMOSFET. By comparing with different contact schemes, the failure mechanism is attributed to Al spiking into the underneath poly-Si and SiO2 during the metallization process. Using suitable blocking layer such as LPCVD Si3N4 (300 nm) or PECVD Si3N4 (100 nm) on SiO2 (200 nm) can avoid Al spiking so that conventional pattern topology and TiAl metallization process can be used on device fabrication.
Well-behaved 4H-SiC PMOSFET with LOCal oxidation of SiC (LOCOSiC) isolation structure and compromised gate oxide for Sub-10V SiC CMOS application
(2020-04-01)
Hung, Chia-Lung
;
Tsui, Bing-Yue
;
電子工程學系及電子研究所
;
Department of Electronics Engineering and Institute of Electronics
SiC devices are suitable for high temperature applications due to its' wide energy bandgap and high thermal conductivity. Some SiC CMOSFET ICs have been reported recently. However, less literature address the characteristics of SiC PMOSFET. In this work, we fabricated PMOSFET with Local Oxidation of SiC (LOCOSiC) isolation structure and different gate oxidation processes targeting sub-10V operation. Well behaved PMOSFET with suitable threshold voltage ( - 5.58 V), low subthreshold swing (200 mV/decade), acceptable hole mobility (3 cm(2)/V-sec), and low off-state current ( < 1 x 10(-12) A/mu m at -10 V) is achieved. Temperature dependence of device characteristics are investigated. These results make the implementation of high-performance CMOS a great progress.