Mechanical Stress of Substrate Coated with Thin Filmexamples|products|Murata Software Co., Ltd.

Example41 Mechanical Stress of Substrate Coated with Thin Film

General

  • 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.

 

 

Analysis Space

Item

Settings

Analysis Space

3D

Model unit

um

 

 

Analysis Conditions

The unit is [um] to cope with thin film.

Item

Settings

Solver

Mechanical Stress Analysis [Galileo]

Analysis Type

Static analysis

Options

N/A

 

Model

The SiGe substrate is a 0.1um thick solid body. The Si film is a 0.01um thick solid body.

 

 

Body Attributes and Materials

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

 

Results

The gradation contour diagram of maximum principal stress is shown below.

The substrate warps due to the lattice mismatch.