Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

MOSFET DC characteristics

Please login with a confirmed email address before reporting spam

hi all,

I am trying to simulate the DC characteristics of MOSFET but when i solve the model i get following errors

Error: 9111
Unknown function
- Function: flgauss
Failed to evaluate variable.
- Variable: Ndoping
- Defined as: (((NDimpl*flgauss(x,y,x1,0,ch))-NAsub)+(flgauss((x2-x),y,x1,0,ch)*NDimpl))
Failed to evaluate variable.
- Variable: p_init
- Defined as: ((((ni^2)/(sqrt(((ni^2)+((Ndoping^2)/4)))+(abs(Ndoping)/2)))*(Ndoping>=0))+(((abs(ndoping)/2)+sqrt(((ni^2)+((ndoping^2)/4))))*(ndoping<0)))
Failed to evaluate variable.
- Variable: phi_init
- Defined as: (((Vt*(((-log((p_init/ni)))*(Ndoping<0))+(log((n_init/ni))*(Ndoping>=0))))-X_si)-(0.5*Eg_si))
Failed to evaluate expression.

whats wrong with this model can anyone please guide me
Regards
waseem

1 Reply Last Post Mar 24, 2011, 8:51 a.m. EDT
Ivar KJELBERG COMSOL Multiphysics(r) fan, retired, former "Senior Expert" at CSEM SA (CH)

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago Mar 24, 2011, 8:51 a.m. EDT
Hi

it says that your function "flgauss", used for Ndoping, which itself is used in the initialisation of "p" and "phi", is not defined

I would start to check the formula for your "Ndoping", are you missing a () or is something not well defined therein ?

--
Good luck
Ivar
Hi it says that your function "flgauss", used for Ndoping, which itself is used in the initialisation of "p" and "phi", is not defined I would start to check the formula for your "Ndoping", are you missing a () or is something not well defined therein ? -- Good luck Ivar

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.