N-Channel MOSFET

Transistor model type:

Number of contacts in the block.

The gain of a MOSFET . This parameter primarily determines the linear region on the characteristic - .

The flat zone voltage defines the gate bias that must be applied to achieve a flat zone state on the silicon surface. It is possible to use this parameter to arbitrarily shift the threshold voltage due to differences in material yield performance and trapped charges at the interface or oxide. However, in practice, it is usually recommended to first change the threshold voltage using the Body factor and Surface potential at strong inversion parameters, and use this parameter only for fine tuning.

The substrate factor in the surface potential equation. This parameter primarily affects the threshold voltage.

The value in the surface potential equation. This parameter also primarily affects the threshold voltage.

The value in the drain current equation. Use this parameter when a good linear fit results in too large a saturation current. Increasing the value of this parameter causes the saturation current to decrease. For high voltage devices, it is often the case that good linear mode matching results in too low a saturation current. In this case the gain and the drain ohmic resistance should be increased.

The coefficient , which is the multiplier of the logarithmic term in the equation for . This parameter describes the onset of channel length modulation. For device characteristics that exhibit positive conduction in saturation, increase the value of the parameter to match this behaviour. The value by default is 0, which means channel length modulation is off.

The voltage in the equation for . This parameter controls the drain voltage at which channel length modulation begins to take effect.

Mobility reduction force. The mobility is equal to , where is the mobility in weak fields without the influence of surface scattering. The mobility reduction factor is defined as , where is the surface roughness scattering coefficient and is the voltage that corresponds to the effective vertical component of the electric field strength in the channel . For high vertical electric fields, electron mobility is approximately proportional to .

This coefficient characterises the smoothness of the transition of the MOSFET characteristic from the linear region to saturation, especially if velocity saturation is enabled. Normally this parameter can be left at its By default value, but you can use it to fine-tune the characteristic curvature - . The expected range of values for this parameter is from 2 to 8.

The temperature , at which the unit parameters are measured. If the value of Device simulation temperature is different from this value, the unit parameters will be determined according to the simulation temperature and reference temperature.

The source resistance of the transistor, that is, the series resistance associated with the source pin. The value must be greater than or equal to 0.

The drain resistance of a transistor, that is, the series resistance associated with the drain pin. The value must be greater than or equal to 0.

The gate resistance of a transistor, that is, the series resistance associated with the gate contact. The value must be greater than or equal to 0.

Transistor substrate resistance, that is, the series resistance associated with the substrate contact.

Dependencies

To use this parameter, set the Number of terminals parameter to Four.

The capacitance between the gate and the channel.

Fixed linear capacitance associated with the gate-source junction.

Fixed linear capacitance associated with the gate-to-drain junction.

Current in the equations for the integrated diode.

Set this parameter to a non-zero value to simulate current flow through the integrated diode for applications where the MOSFET current changes sign during simulation, such as when the MOSFET drives an inductive load.

For applications where the MOSFET current never changes sign, such as in a small signal amplifier, set this parameter to 0 to increase the simulation speed.

The embedded diode voltage in the equations for the embedded diode. This voltage only affects the junction capacitance equation. It does not affect the conduction current.

The ideality factor in the equations for the integrated diode.

The capacitance between drain and substrate at zero bias due to the integrated diode only, in the equations for the integrated diode.

Time in the equations for the integrated diode.

If the values of the Reverse saturation current and Transit time parameters are non-zero, the block includes reverse recovery in the embedded diode model.

Select one of the following methods for parameterising the temperature dependence:

The gain of the MOSFET is assumed to be exponentially dependent on temperature: , where is the value of the Gain parameter and is the value of the Gain temperature exponent parameter.

Dependencies

To use this parameter, set the Parameterization parameter to `Model temperature dependence'.

The flatband voltage is assumed to be linearly dependent on temperature: , where is the value of the Flatband voltage parameter and is the value of the Flatband voltage temperature coefficient parameter.

Dependencies

To use this parameter, set the Parameterization parameter to `Model temperature dependence'.

The surface potential at strong inversion is assumed to depend linearly on temperature: , where is the value of Surface potential at strong inversion and is the value of Surface potential at strong inversion temperature coefficient.

Dependencies

To use this parameter, set the Parameterization parameter to `Model temperature dependence'.

The velocity saturation is assumed to be exponentially dependent on temperature: , where is the value of the Velocity saturation factor parameter and is the value of the Velocity saturation temperature exponent parameter.

Dependencies

To use this parameter, set the Parameterization parameter to `Model temperature dependence'.

This parameter leads to a temperature-dependent decrease in the conductivity of the MOSFET at high gate voltage.

The surface roughness scattering factor is assumed to depend exponentially on temperature: , where is the value of the Surface roughness scattering factor and is the value of the Surface roughness scattering temperature exponent.

Dependencies

To use this parameter, set the Parameterization parameter to `Model temperature dependence'.

Series resistances are assumed to correspond to semiconductor resistances. Therefore, they decrease exponentially with increasing temperature: , where is , or for source, drain or gate resistance, respectively, is the value of the corresponding Source ohmic resistance, Drain ohmic resistance or Gate ohmic resistance parameter, and is the value of the Resistance temperature exponent parameter.

Dependencies

To use this parameter, set the Parameterization parameter to Model temperature dependence.

The inverse saturation current for an integrated diode is assumed to be proportional to the square of the concentration of intrinsic carriers: , where is the temperature-dependent effective density of states and is the temperature-dependent bandgap width for the semiconductor material. In order not to introduce another parameter for the temperature dependence, the temperature dependence of the forbidden zone width is neglected in the block and the forbidden zone width of silicon at 300 K (1.12 eV) is used for all types of devices. Thus, the temperature dependence of the reverse saturation current is defined as follows:

Where is the value of the Reverse saturation current parameter, is the Boltzmann constant, is the value of the Body diode reverse saturation current temperature exponent parameter. The value by default is 3 since for silicon is roughly proportional to . It is possible to account for the temperature dependence of the forbidden band width by adjusting the value of .

Dependencies

To use this parameter, set the Parameterization parameter to Model temperature dependence.

Temperature , for which the device simulation is performed.

Dependencies

To use this parameter, set the Parameterization parameter to Model temperature dependence.

To enable thermal effects modelling, select the check box for this parameter.

Select the internal thermal model:

The [R_JC R_CA] vector of two values of thermal resistance. The first value, R_JC, is the thermal resistance between the junction and the chassis. The second value, R_CA is the thermal resistance between the H port and the device enclosure.

Dependencies

To use this parameter, set the Thermal network parameter to Specify junction and case thermal parameters.

A vector of values of the thermal resistances represented by the Kauer elements in the thermal network. All these values must be greater than zero.

Dependencies

To use this parameter, set the Thermal network parameter to Cauer model.

A vector of values of thermal resistances represented by the Foster model coefficients in the heat network. All these values must be greater than zero.

Dependencies

To use this parameter, set the Thermal network parameter to `Cauer model parameterised with Foster coefficients'.

Select the method for specifying the heat capacity:

Dependencies

To use this parameter, set the Thermal network parameter to Specify junction and case thermal parameters, Cauer model or Cauer model parameterised with Foster coefficients.

The vector [M_J M_C] of two heat capacity values. The first value M_J is the heat capacity of the transition. The second value, M_C, is the heat capacity of the case.

Dependencies

To use this parameter, set the Thermal network parameter to `Specify junction and case thermal parameters' and the Thermal mass parameterization parameter to `By thermal mass'.

A vector of heat capacity values, where is the number of Kauer model coefficients in the heat network. All these values must be greater than zero.

Dependencies

To use this parameter, set the Thermal network parameter to `Cauer model' and the Thermal mass parameterization parameter to `By thermal mass'.

A vector of heat capacity values, where is the number of Foster elements in the heat network. All these values must be greater than zero.

Dependencies

To use this parameter, set the Thermal network parameter to `Cauer model parameterised with Foster coefficients' and the Thermal mass parameterization parameter to `By thermal mass'.

A vector [t_J t_C] of two values of thermal time constants. The first value, t_J, is the thermal time constant of the transition. The second value, t_C is the thermal time constant of the body.

Dependencies

To use this parameter, set the Thermal network parameter to Specify junction and case thermal parameters and the Thermal mass parameterization parameter to By thermal time constants.

A vector of values of thermal time constants, where is the number of Kauer elements in the thermal network. All these values must be greater than zero.

The heat capacity value is calculated as , where , and are the heat capacity, thermal time constant and thermal resistance for the -th Cauer element.

Dependencies

To use this parameter, set the Thermal network parameter to `Cauer model' and the Thermal mass parameterization parameter to `By thermal time constants'.

A vector of values of thermal time constants, where is the number of Foster model coefficients in the thermal network. All these values must be greater than zero.

The heat capacity value is calculated as , where , and are the heat capacity, thermal time constant and thermal resistance for the -th Cauer element.

Dependencies

To use this parameter, set the Thermal network parameter to `Cauer model parameterised with Foster coefficients' and the Thermal mass parameterization parameter to `By thermal time constants'.

Vector [T_J T_C] of two temperature values. The first value, T_J, is the initial transition temperature. The second value, T_C is the initial case temperature.

Dependencies

To use this parameter, set the Thermal network parameter to Specify junction and case thermal parameters.

A vector of temperature values. It corresponds to the temperature difference for each heat capacity in the model.

Dependencies

To use this parameter, set the Thermal network parameter to Cauer model.

A vector of absolute temperature values for each element of the Foster model.

Dependencies

To use this parameter, set the Thermal network parameter to `Cauer model parameterised with Foster coefficients'.