as the shock shafts of radio controlled cars. TiN is also used as a protective coating on the moving parts of many rifles and semi automatic firearms, as it is extremely durable. As well as being durable, it is also extremely smooth, making removing the carbon build up extremely easy. TiN is non-toxic, meets FDA guidelines and has seen use in medical devices such as scalpel blades and orthopedic bone saw blades where sharpness and edge retention are important. TiN coatings have also been used in implanted prostheses (especially hip replacement implants) and other medical implants. Though less visible, thin films of TiN are also used in microelectronics, where they serve as a conductive connection between the active device and the metal contacts used to operate the circuit, while acting as a diffusion barrier to block the diffusion of the metal into the silicon. In this context, TiN is classified as a "barrier metal" (electrical resistivity ~ 25 µΩ·cm), even though it is clearly a ceramic from the perspective of chemistry or mechanical behavior. Recent chip design in the 45 nm technology and beyond also makes use of TiN as a "metal" for improved transistor performance. In combination with gate dielectrics (e.g. HfSiO) that have a higher permittivity compared to standard SiO2 the gate length can be scaled down with low leakage, higher drive current and the same or better threshold voltage. Additionally, TiN thin films are currently under consideration for coating zirconium alloys for accident-tolerant nuclear fuels. It is also used as a coating on some compression driver diaphragms to improve performance. Owing to their high biostability, TiN layers may also be used as electrodes in bioelectronic applications like in intelligent implants or in-vivo biosensors that have to withstand the severe corrosion caused by body fluids. TiN electrodes have already been applied in the subretinal prosthesis project as well as in biomedical microelectromechanical systems (BioMEMS). Fabrication The most common methods of TiN thin film creation are physical vapor deposition (PVD, usually sputter deposition, cathodic arc deposition or electron beam heating) and chemical vapor deposition (CVD). In both methods, pure titanium is sublimed and reacted with nitrogen in a high-energy, vacuum environment. TiN film may also be produced on Ti workpieces by reactive growth (for example, annealing) in a nitrogen atmosphere. PVD is preferred for steel parts because the deposition temperatures exceeds the austenitizing temperature of steel. TiN layers are