CAE Software【Femtet】Murata Software Co., Ltd.
A SiGe substrate is coated with a thin Si film. The mechanical stresses are generated due to the mismatch of their lattices.
Lattice mismatch ratio = (Thin film’s lattice constant – Substrate’s lattice constant) / Substrate’s lattice constance
The tensile stress is solved under the condition that the lattice mismatch ratio is -0.1% .
Unless specified in the list below, the default conditions will be applied.
Item |
Settings |
Analysis Space |
3D |
Model unit |
um |
The unit is [um] to cope with thin film.
Item |
Settings |
Solver |
Mechanical Stress Analysis [Galileo] |
Analysis Type |
Static analysis |
Options |
N/A |
The SiGe substrate is a 0.1um thick solid body. The Si film is a 0.01um thick solid body.
Body Number/Type |
Body Attribute Name |
Material Name |
0/Solid |
SiGeLayer |
301_Silicon(single-crystal) * |
1/Solid |
SiLayer |
301_Silicon(single-crystal) * |
* Available from the Material DB
The initial strain (axial) is set to -0.001 on the Initial Strain tab of SiLayer. This is equivalent to -0.1% lattice mismatch.
SiLayer shrinks by 0.1% during the simulation.
Body Attribute Name |
Initial Strain |
SiLayer |
Axial strain/Isotropic/-0.001 |
The gradation contour diagram of maximum principal stress is shown below.
The substrate warps due to the lattice mismatch.