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# nonlinear Coss behavior in SiC MOSFETs

## nonlinear Coss behavior in SiC MOSFETs

Level 3
Level 3

Dear IFXer,

As far as I know, the nonlinear Coss of SJ MOSFET is caused by the depletion region between the p-pillar and the epitaxial n-layer on the drain-source voltage

and would like to know what the nonlinear Coss behavior is in SiC MOSFETs, including both planar and trench of gate structures?

1 Solution

## Re: nonlinear Coss behavior in SiC MOSFETs

Moderator
Moderator

Dear @WEN-YUNG ,
Greetings from Infineon,
Thanks for posting your query in Infineon Community.

Parasitic capacitance of SiC Mosfets are as below

Output capacitance = Cds+Cgd
where,
Cds = drain to source capacitance

Cgd = gate to drain capacitance

Cgs, Cgd and Cds are  known as stray capacitance, parasitic capacitance is unavoidable and that exists between the parts of an electronic component or circuit simply because of how close they are to one another.

Capacitance is the ability of a system to store an electric charge.

The Gate terminal in a MOSFET is isolated from the other terminals by an oxide film. The silicon under the gate has the opposite polarity to the drain and source which results in the formation of PN junctions (diode) between the Gate, Drain and Source regions. Cgs and Cgd are the capacitances of the oxide layers, while Cds is determined by the junction capacitance of the internal diode

For ex. IMZA120R007M1H (SiC MOSFET, VDSS = 1200 V, rated current = 225 A , Trench gate)
The Coss non-linear behaviour as below.

I hope this helps,
Kindly let us know if you have any further queries.

Best regards,
Santhosh Kumar

## Re: nonlinear Coss behavior in SiC MOSFETs

Moderator
Moderator

Dear @WEN-YUNG ,
Greetings from Infineon,
Thanks for posting your query in Infineon Community.

Parasitic capacitance of SiC Mosfets are as below

Output capacitance = Cds+Cgd
where,
Cds = drain to source capacitance

Cgd = gate to drain capacitance

Cgs, Cgd and Cds are  known as stray capacitance, parasitic capacitance is unavoidable and that exists between the parts of an electronic component or circuit simply because of how close they are to one another.

Capacitance is the ability of a system to store an electric charge.

The Gate terminal in a MOSFET is isolated from the other terminals by an oxide film. The silicon under the gate has the opposite polarity to the drain and source which results in the formation of PN junctions (diode) between the Gate, Drain and Source regions. Cgs and Cgd are the capacitances of the oxide layers, while Cds is determined by the junction capacitance of the internal diode

For ex. IMZA120R007M1H (SiC MOSFET, VDSS = 1200 V, rated current = 225 A , Trench gate)
The Coss non-linear behaviour as below.

I hope this helps,
Kindly let us know if you have any further queries.

Best regards,
Santhosh Kumar