Who can tell me the microscopic mechanics of electric polarition of Si3N4

[hjq_seu]

Si3N4 is an amorphous.What's the microscopic structure of it and Which type of polarization is involved when it is presented in an Electric field(Eletronic polarization,orientational polarization,Atomic ploraization or some others)?Is there any theories to calculate the permittivity of Si3Ni4
By the way, I want to know if the molecule of Si3N4 combined by ionic bonds or atomic bonds?Thank you!

 

[Gokul43201]

Silicon nitride is a mostly covalently bonded molecule (hence the amorphousness). Under certain deposition conditions, however, it may possibly take on crystal characteristics similar to the substrate (but I'm not sure about this).

The dielectric properties of Si3N4 are pretty well known. It has been studied since the 70s as a possible gate dielectric. It has a relative permittivity (dielectric constant) of 7.8, which is greater than that of SiO2. It has recently regained the interest of fabrication folk for possible use in MOSFETs and more easily in nanotube-based FETs.

1. B Swaroop et al J. Phys. D: Appl. Phys. 3 803-806 (1970)

2. S Li, Z Yu, P Burke J. Vac. Sci. Technol. B 22(6) 3112 - 3114 (2004)