Applications of silicon nitride

Applications of silicon nitride

The unique electrical properties of silicon nitride have caused an increasing usage in microelectronics applications as an insulator and chemical barrier in the manufacture of integrated circuits for the protective packaging of devices. Silicon nitride is used as a passivation layer with a high diffusion barrier against water and sodium ions, both of which are major sources of corrosion and instability in microelectronics. The material is also used as an electrical insulator between polysilicon layers in capacitors of analog chips. Silicon nitride also found use in the xerographic process as one of the photo drum layers. Owing to its excellent elastic properties, silicon nitride has been the most accepted material for cantilevers, which are the sensing elements for atomic force microscopes.

The use of silicon nitride has also been recognized in the field of optics, having great transparency in the spectral range, giving rise to Si3N4 photonics. The broadband nature of Si3N4 has allowed it to be used in biochemical and biomedical optical applications, biophotonics, tele- and data communications, and optical signal processing, sensing from visible through near to mid-infrared wavelengths.

DENTAL APPLICATIONS

Having demonstrated itself as an beneficial implant material for spinal implants , researchers have turned to the potential of silicon nitride for dental implants and craniomaxillofacial implants as well. In an article posted by The American Ceramic Society, silicon nitride was labeled as a “killer ceramic material,” due to its antibacterial property that inhibits Porphyromonas gingivalis, a bacterium found in oral cavities that causes gum disease. In this joint research invitro study, the bacteria underwent lysis (breaking down of the cell, often by viral, enzymic, or osmotic mechanisms that compromise its integrity) on polished surfaces of silicon nitride material. Silicon nitride demonstrated the ability to degrade the bacteria’s biological makeup in six days. This breakdown of cell function was primarily due to the formation of peroxynitrite, an oxidizing and nitrating agent capable of damaging molecules in cells, including DNA and proteins. The research study also found out that altering the surface chemistry of silicon nitride will influence the formation of peroxynitrite and thus affect bacteria metabolism in various ways. The unique properties of silicon nitride demonstrate potential in oral health applications.

There has been an increasing demand for metal-free dental implants and has contributed to the interest in silicon nitride material for the potential dental implant global market.