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modelling of wrap around gate using FEM in COMSOL
Posted 17.03.2017, 02:54 GMT-4 2 Replies
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Hii
we are doing a project on "modelling of wrap around gate using FEM in COMSOL we found a few problems regarding the simulation.
Can somebody please help us with this.
we completed the part of geometry and assigning of the materials and analytic doping models, metal contacts and assigning the mesh with the reference of 2d characteristics of MOSFET
Thank you
Undefined variable.
- Variable: T
- Geometry: geom1
- Domain: 2
Failed to evaluate variable.
- Variable: comp1.semi.Nc
- Defined as: (((T/(unit_K_cf*300))^1.5)*28000000000000000000)/(unit_cm_cf^3)
Failed to evaluate expression.
- Expression: subst(comp1.semi.Nc,comp1.semi.Tl,comp1.semi.T0)
Failed to evaluate variable.
- Variable: comp1.semi.Nc_init
- Defined as: eps+subst(comp1.semi.Nc,comp1.semi.Tl,comp1.semi.T0)
Failed to evaluate variable.
- Variable: comp1.semi.ni_init
- Defined as: sqrt(comp1.semi.Nc_init*comp1.semi.Nv_init)*exp(((-0.5)*comp1.semi.Eg_init)/comp1.semi.Vth_init)
Failed to evaluate variable.
- Variable: comp1.semi.n_init
- Defined as: ((comp1.semi.Ndoping_init>=0)*((0.5*abs(comp1.semi.Ndoping_init))+sqrt(((0.5*comp1.semi.Ndoping_init)^2)+(comp1.semi.ni_init^2))))+(((comp1.semi.ni_init^2)*(comp1.semi.Ndoping_init<0))/((0.5*abs(comp1.semi.Ndoping_init))+sqrt(((0.5*comp1.semi.Ndoping_init)^2)+(comp1.semi.ni_init^2))))
Failed to evaluate variable.
- Variable: comp1.semi.V_init
- Defined as: (((comp1.semi.Vth_init*(((comp1.semi.Ndoping_init>=0)*log(comp1.semi.n_init/comp1.semi.ni_init))+((-log(comp1.semi.p_init/comp1.semi.ni_init))*(comp1.semi.Ndoping_init<0))))-comp1.semi.chi_init)-(comp1.semi.Eg_init*0.5))+((comp1.semi.Vth_init*0.5)*log(comp1.semi.Nv_init/comp1.semi.Nc_init))
Failed to evaluate expression.
- Expression: comp1.semi.V_init
- Feature: Dependent Variables 1 (sol1/v1)
we are doing a project on "modelling of wrap around gate using FEM in COMSOL we found a few problems regarding the simulation.
Can somebody please help us with this.
we completed the part of geometry and assigning of the materials and analytic doping models, metal contacts and assigning the mesh with the reference of 2d characteristics of MOSFET
Thank you
Undefined variable.
- Variable: T
- Geometry: geom1
- Domain: 2
Failed to evaluate variable.
- Variable: comp1.semi.Nc
- Defined as: (((T/(unit_K_cf*300))^1.5)*28000000000000000000)/(unit_cm_cf^3)
Failed to evaluate expression.
- Expression: subst(comp1.semi.Nc,comp1.semi.Tl,comp1.semi.T0)
Failed to evaluate variable.
- Variable: comp1.semi.Nc_init
- Defined as: eps+subst(comp1.semi.Nc,comp1.semi.Tl,comp1.semi.T0)
Failed to evaluate variable.
- Variable: comp1.semi.ni_init
- Defined as: sqrt(comp1.semi.Nc_init*comp1.semi.Nv_init)*exp(((-0.5)*comp1.semi.Eg_init)/comp1.semi.Vth_init)
Failed to evaluate variable.
- Variable: comp1.semi.n_init
- Defined as: ((comp1.semi.Ndoping_init>=0)*((0.5*abs(comp1.semi.Ndoping_init))+sqrt(((0.5*comp1.semi.Ndoping_init)^2)+(comp1.semi.ni_init^2))))+(((comp1.semi.ni_init^2)*(comp1.semi.Ndoping_init<0))/((0.5*abs(comp1.semi.Ndoping_init))+sqrt(((0.5*comp1.semi.Ndoping_init)^2)+(comp1.semi.ni_init^2))))
Failed to evaluate variable.
- Variable: comp1.semi.V_init
- Defined as: (((comp1.semi.Vth_init*(((comp1.semi.Ndoping_init>=0)*log(comp1.semi.n_init/comp1.semi.ni_init))+((-log(comp1.semi.p_init/comp1.semi.ni_init))*(comp1.semi.Ndoping_init<0))))-comp1.semi.chi_init)-(comp1.semi.Eg_init*0.5))+((comp1.semi.Vth_init*0.5)*log(comp1.semi.Nv_init/comp1.semi.Nc_init))
Failed to evaluate expression.
- Expression: comp1.semi.V_init
- Feature: Dependent Variables 1 (sol1/v1)
2 Replies Last Post 18.03.2017, 01:37 GMT-4
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Posted:
7 years ago
Hello,
This error indicates the COMSOL does not know the meaning of "T" in domain 2. The next part of the error message says that COMSOL cannot evaluate the variable comp1.semi.Nc, which involves "T" in its definition. -DW
Undefined variable.
- Variable: T
- Geometry: geom1
- Domain: 2
Failed to evaluate variable.
- Variable: comp1.semi.Nc
This error indicates the COMSOL does not know the meaning of "T" in domain 2. The next part of the error message says that COMSOL cannot evaluate the variable comp1.semi.Nc, which involves "T" in its definition. -DW
Undefined variable.
- Variable: T
- Geometry: geom1
- Domain: 2
Failed to evaluate variable.
- Variable: comp1.semi.Nc
Please login with a confirmed email address before reporting spam
Posted:
7 years ago
hello
we removed those errors sir. But i have a doubt regarding the CNTFET. As the substrate is p then the channel is also p . Now in our project we made the source as ground and defined the gate dielectric as hafnium oxide and gate material is polysilicon. Now to make the gate contact we need to select all the boundaries of the upper cylinder i.e., gate material but the selection is not working in this regard. if we solve this can we plot the graphs???
can somebody please help us with this
Thank you
we removed those errors sir. But i have a doubt regarding the CNTFET. As the substrate is p then the channel is also p . Now in our project we made the source as ground and defined the gate dielectric as hafnium oxide and gate material is polysilicon. Now to make the gate contact we need to select all the boundaries of the upper cylinder i.e., gate material but the selection is not working in this regard. if we solve this can we plot the graphs???
can somebody please help us with this
Thank you