| Author | Message | |||||
     ferrier (marlene) Member Username: marlene Post Number: 4 Registered: 04-2007 |
Hello; In the structure I simulate, the rectangular region 1, made of material 1 is on the top of the rectangular region 2 (made of material 2). I'd like that the edge of these two regions exhibit the properties of the lower material. I have tried to declare the upper region and then the lower region, I have tried the opposite but I can't have the properties I wish for the "border". + If I apply a positive bias on the top of he structure, the potential energy along the boudary suddenly seems to be computed using the caracteristic of the lower material (which is good). Do you have any explanation or advice? Thanks for your help + I use the student version | |||||
| Marek Nelson (mgnelson) Moderator Username: mgnelson Post Number: 2 Registered: 07-2007 |
Please post your script showing what you have tried. Without them it is difficult to comment. | |||||
| ferrier (marlene) Member Username: marlene Post Number: 5 Registered: 04-2007 |
Here it is As you will se, in that example, the upper region (gate oxide) is defined after the lower region (oxide channel). But the border in between exhibits the channel properties of the lower material. It is what I want, but I don't understand why it is this way + If I simulate only VG=0, the border will exhibit the properties of upper material If i simulate a bunch of VG values, the material properties of the boders will be the ones of the lower material (however it has been defined first) including for VG=0 Id like to understand what is going on and how to make sure the paterial properties at the borders are always the one i want Thanks for your help I am looking forward to read your answer
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| ferrier (marlene) Member Username: marlene Post Number: 6 Registered: 04-2007 |
Here it is As you will se, in that example, the upper region (gate oxide) is defined after the lower region (oxide channel). But the border in between exhibits the channel properties of the lower material. It is what I want, but I don't understand why it is this way + If I simulate only VG=0, the border will exhibit the properties of upper material If I simulate a bunch of VG values, the material properties of the boders will be the ones of the lower material (however it has been defined first) including for VG=0 I'd like to understand what is going on and how to make sure the material properties at the borders are always the one i want Thanks for your help I am looking forward to read your answer
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| Marek Nelson (mgnelson) Moderator Username: mgnelson Post Number: 3 Registered: 07-2007 |
I'm not sure what you are asking. Boundaries do not take on material properties, only regions. If you mean the value of your variable at the boundary, it is dictated by your other boundary conditions and flux continuity at the interface (since you have specified natural=0 on that boundary). I do notice several problems with your script : 1) The boundary conditions at the bottom corner points of region 1 are discontinuous. Value(V)=Vg2 on the bottom edge and 0 or Vd on the left or right. With the student version, regridding is limited but with the professional version, this causes infinite regridding in an attempt to resolve this discontinuity. 2) Your boundary conditions on the sides of region 1 are multiply defined. Natural(V)=0 in region 1 and Value(V)=0 and Vd on the left and right. 3) There are two undefined names in your script. Eox in the plots and Eoxmid in your histories. I had to comment these out in order to run the problem. |
