Mechanical Properties of Silicon Microstructures

Mechanical properties of silicon microstructures and basic structural properties of crystalline silicon are discussed here. At ordinary pressure silicon crystallizes in a diamond structure with a basis of two atoms. All the theoretical calculations using force-field methods correctly describe bulk silicon in its diamond structure ground state, giving a value for the lattice parameter that is close to the value that is experimentally observed. Effects of pressure are explained here in detail. At high-elastic strains the harmonic approximation becomes insufficient to correctly describe the elastic energy. An alternative way to treat the nonlinearity effects is to include the higher than second-order terms in the formal expansion of the elastic energy in strains. Extended defects could be classified with respect to their dimensionality. The partial dislocations are always associated with stacking faults. Two types of dislocation in silicon are of special interest. Silicon has been a favorite material for theoretical and experimental investigations of dislocation nature and mobility. The second approach is the so-called cluster method, where a finite cluster surrounding the defect is constructed. Some examples of the proposed core reconstruction are presented. The dislocation segment where the dislocation line jumps over the Peierls barrier is called kink. Silicon belongs to the class of intrinsically brittle solids. The convenience and success of silicon material and micromachining technology have made silicon a natural choice for many MEMS applications, such as actuator, power generator, etc. The reliability of these applications is extremely important to ensure their effective performance.