N-Channel MOSFET

Transistor Model Type:

The number of contacts in the block.

MOSFET gain . This parameter primarily determines the linear area on the characteristic - .

Flat zone voltage determines the gate offset that must be applied to achieve a flat zone state on the silicon surface. You can use this parameter to arbitrarily shift the threshold voltage due to differences in the output of the materials, as well as due to 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 equation of the surface potential. This parameter primarily affects the threshold voltage.

Value in the equation of the surface potential. This parameter also primarily affects the threshold voltage.

Value in the drain current equation. Use this parameter in cases where good compliance with the linear mode results in too much saturation current. Increasing the value of this parameter leads to a decrease in the saturation current. For high-voltage devices, it often happens that good compliance with the linear mode leads to too low saturation current. In this case, the gain and ohmic resistance of the drain should be increased.

Ratio , which is the multiplier of the logarithmic term in the equation for . This parameter describes the beginning of the channel length modulation. For the characteristics of a device that exhibits positive saturation conductivity, increase the parameter value to match this behavior. The default value is 0, which means the channel length modulation is disabled.

Voltage in the equation for . This parameter controls the drain voltage at which channel length modulation begins to operate.

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

This coefficient characterizes the smooth transition of the MOSFET characteristic from the linear region to saturation, especially if speed saturation is enabled. This parameter can usually be left at the default value, but you can use it to fine-tune the bending characteristic. - . The expected range of values for this parameter is from 2 before 8.

Temperature , at which the block parameters are measured. If the value of the Device simulation temperature parameter differs from this value, the device parameters will be determined according to the simulation temperature and the reference temperature.

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

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

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

The resistance of the transistor substrate, that is, the series resistance associated with the substrate contact.

Dependencies

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

The capacity between the gate and the channel.

Fixed linear capacitance associated with the gate-source junction.

Fixed linear capacity associated with the gate-drain junction.

Current in the equations for the built-in diode.

Set this parameter to a non-zero value to simulate the passage of current through the built-in diode, for applications where the MOSFET current changes sign during simulation, for example, 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.

Voltage of the built-in diode in the equations for the built-in diode. This voltage only affects the junction capacitance equation. It does not affect the conduction current.

The coefficient of ideality in the equations for the built-in diode.

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

Time in the equations for the built-in diode.

If the values of the Reverse saturation current and Transit time parameters are non-zero, then the block enables reverse recovery to the built-in diode model.

Choose one of the following methods for parameterizing the temperature dependence:

It is assumed that the gain of the MOSFET exponentially depends on temperature: , where — this is the value of the Gain parameter, and — the value of the Gain temperature exponent parameter.

Dependencies

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

It is assumed that the voltage of the flat zone linearly dependent on temperature: , where — this is the value of the Flatband voltage parameter, and — this is the value of the Flatband voltage temperature coefficient parameter.

Dependencies

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

It is assumed that the surface potential under strong inversion linearly dependent on temperature: , where — this is the value of the Surface potential at strong inversion parameter, and — this is the value of the Surface potential at strong inversion temperature coefficient parameter.

Dependencies

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

It is assumed that the saturation of the speed exponentially depends on temperature: , where — this is the value of the Velocity saturation factor parameter, and — 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.

It is assumed that the scattering coefficient of the surface roughness exponentially depends on temperature: , where — this is the value of the Surface roughness scattering factor parameter, and — the value of the Surface roughness scattering temperature exponent parameter.

Dependencies

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

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

Dependencies

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

It is assumed that the reverse saturation current for the built-in diode is proportional to the square of the concentration of its own carriers.: , where is the temperature—dependent effective density of states, and is the temperature—dependent band gap for a semiconductor material. In order not to introduce another parameter for the temperature dependence, the block neglects the temperature dependence of the band gap width and uses the silicon band gap at 300 K (1.12 eV) for all types of devices. Thus, the temperature dependence of the reverse saturation current is determined as follows:

where — the value of the parameter Reverse saturation current, — Boltzmann constant, — the value of the Body diode reverse saturation current temperature exponent parameter. The default value is 3 because for silicon, approximately proportionally . It is possible to take into account the temperature dependence of the band gap width by adjusting the value .

Dependencies

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

Temperature , for which the device is being modeled.

Dependencies

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

To enable the simulation of thermal effects, select the checkbox for this option.

Choose an internal thermal model:

Vector [R_JC, R_CA] of the two values of thermal resistance. The first value R_JC — this is the thermal resistance between the junction and the housing. The second value, R_CA — this is the thermal resistance between the H port and the device body.

Dependencies

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

Vector from the values of the thermal resistances represented by the Kauer elements in the heating network. All these values must be greater than zero.

Dependencies

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

Vector from the values of thermal resistances represented by the coefficients of the Foster model in the heating network. All these values must be greater than zero.

Dependencies

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

Choose a method for setting 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 parameterized with Foster coefficients.

Vector [M_J, M_C] of the two values of the heat capacity. The first value M_J — this is the heat capacity of the transition. The second value, M_C — this 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 for the parameter Thermal mass parameterization the value By thermal mass.

Vector from values of heat capacities, where this is the number of coefficients of the Kauer model 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 for the parameter Thermal mass parameterization the value By thermal mass.

Vector from values of heat capacities, where this is the number of Foster elements in the heating network. All these values must be greater than zero.

Dependencies

To use this parameter, set the Thermal network parameter to Cauer model parameterized with Foster coefficients, and for the parameter Thermal mass parameterization the value By thermal mass.

Vector [t_J, t_C] of the two values of the thermal time constants. The first value t_J — this is the thermal constant of the transition time. The second value, t_C — this is the thermal time constant of the hull.

Dependencies

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

Vector from values of thermal time constants, where this is the number of Kauer elements in the heating network. All these values must be greater than zero.

The value of the heat capacity is calculated as , where , and — heat capacity, thermal time constant and thermal resistance for - the go element of the Cowera.

Dependencies

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

Vector from values of thermal time constants, where this is the number of coefficients of the Foster model in the heating network. All these values must be greater than zero.

The value of the heat capacity is calculated as , where , and — heat capacity, thermal time constant and thermal resistance for - the go element of the Cowera.

Dependencies

To use this parameter, set the Thermal network parameter to Cauer model parameterized with Foster coefficients, and for the parameter Thermal mass parameterization the value By thermal time constants.

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

Dependencies

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

The 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.

The vector of absolute temperature values of each element of the Foster model.

Dependencies

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