The New Technology And Related Effects Research Of The Wafer-level Biaxial Strain SOI

Since intergret circuit getted into the ultra-deep submicron era,the degradation of carrier mobility and the parasitics effects have became an important factor to control its development.Since then,the strained SOI technology combining strained silicon technology and silicon-on-insulator technology produces.It can greatly improve the carrier mobility and reduce the parasitic effects and is usually used in high-speed and low-power circuits.Wafer-level strain technology is one of the best strained SOI technology.Wafer-level strain SOI can be adapted to each process node,especially suitable for domestic backward integrated circuit manufacturing level.Based on the theory of elastic-plastic mechanics,the properties of SOI materials,the interface properties of the SOI materials and the high stress properties of Si₃N₄?silicon nitride?thin films,the paper introduces a new method to perparation the wafer-level biaxal strain SOI,which use the high stress properties of Si₃N₄ thin films to introduce stress and high temperature annealing to remember strss.The new method has the properties of a simple process,the large amount of strain and so on.The stress introduction mechanism and stress maintaining mechanism of the method are also described,which provides a theoretical basis for the preparation of biaxial strain SOI caused by high stress Si₃N₄ film.In this paper,the preparation technology and characteristics of high stress silicon nitride thin film were studied in detail.Based on the process characteristics of PECVD,the deposition experiment of Si₃N₄ thin film was carried out.The compressive stress Si₃N₄ film with stress of up to 1GPa and the tensile stress Si₃N₄ film with stress of up to 1GPa are manufactured.Based on the material properties of SOI wafer and Si₃N₄ thin films,the interface properties of the SOI materials and the theory of elastic-plastic mechanics,the stress generation,stress introduction and stress maintaining mechanism of the preparation method were studied systematically.And a finite element simulation model of a silicon wafer on which deposit with high stress silicon nitride deposition was established.The model was used to calculate the change of bending degree after depositing stress silicon nitride film.Based on the stress characteristics of Si₃N₄ thin films,the structural characteristics of SOI materials and its interfacial properties,the strain mechanism of Si₃N₄ induced SOI and the principle of PECVD process,the fabrication method of Si₃N₄ induced strain SOI was proposed.The technological principle of fabrication method was also discussed.The results show that the wafer-level biaxial strain SOI samples with a sheet strain of 0.3%are obtained.