High-k Dielectrics - Use in Industry

Use in Industry

The industry has employed oxynitride gate dielectrics since the 1990s, wherein a conventionally formed silicon oxide dielectric is infused with a small amount of nitrogen. The nitride content subtly raises the dielectric constant and is thought to offer other advantages, such as resistance against dopant diffusion through the gate dielectric.

In early 2007, Intel announced the deployment of hafnium-based high-k dielectrics in conjunction with a metallic gate for components built on 45 nanometer technologies, and has shipped it in the 2007 processor series codenamed Penryn. At the same time, IBM announced plans to transition to high-k materials, also hafnium-based, for some products in 2008. While not identified, it is most likely the dielectrics used by these companies are some form of nitrided hafnium silicates (HfSiON). HfO₂ and HfSiO are susceptible to crystallization during dopant activation annealing. NEC Electronics has also announced the use of a HfSiON dielectric in their 55 nm UltimateLowPower technology. However, even HfSiON is susceptible to trap-related leakage currents, which tend to increase with stress over device lifetime. The higher the hafnium concentration, the more severe the issue. However, there is no guarantee that hafnium will be the basis of future high-k dielectrics. The 2006 ITRS roadmap predicted the implementation of high-k materials to be commonplace in the industry by 2010.