Mechanical strengths of silicon nitrides studied by ab initio calculations

作者：Zhang R F^*; Sheng S H; Veprek S

来源：Applied Physics Letters, 2007, 90(19): 191903.

DOI：10.1063/1.2737376

The stress-strain relationships under tensile and shear loads are calculated for hcp(beta)-Si3N4 and fcc(NaCl)-SiN by means of ab initio density functional theory. The ideal shear strengths for fcc-SiN are much lower than those for hcp-Si3N4. This is in agreement with experiments which show that the interfacial fcc-SiN can strengthen the TiN/SiN heterostructures only when its thickness is about 1-2 ML. Based on the calculated electronic density of states, the physical origin of the mechanical strengths is addressed.

• 出版日期2007-5-7