Utilize constant EPSSIL in Modelica.Electrical.Spice3.Internal.Mos1.mos1ModelLineParamsInitEquations

[beutlich]

Already utilized in other place.

[HansOlsson]

As noted in #4377 we might also document that epssil means epsilon (di-electric constant) for Silicon, and add a proper unit.

[beutlich]

As noted in #4377 we might also document that epssil means epsilon (di-electric constant) for Silicon, and add a proper unit.

I updated the descriptions accordingly but will change the units of EPSSIL and EPSSOX in a separate PR once this PR gets merged, because this PR does not introduce any simulation relevant changes.

[HansOlsson]

Looks ok.
There are also other changes we can do later.
However, e.g., using

constant SI.HeatCapacity CONSTboltz = Modelica.Constants.k; // J/K
constant SI.Charge CHARGE = Modelica.Constants.q; 
constant Real EPSSIL = 11.7 * Modelica.Constants.epsilon_0 "Absolute permittivity of silicon"; // F/m

requires testing.

Others that should be harmless are:

constant SI.Temperature CONSTCtoK = Modelica.Units.Conversions.from_degC(0);
constant SI.Temperature REFTEMP = Modelica.Units.Conversions.from_degC(27);
constant Real CONSTvt0(final unit="(J)/(A.s)") = Modelica.Constants.k * REFTEMP / CHARGE; // deg C

(And likely remove the final deg C.)