4.2. Hafnium dioxide (HfO2)

HfO2 is second most promising dielectric on SiC surface after SiO2 due to its high dielectric constant and very high breakdown voltage. A good quality and desired thickness can be easily achieved in laboratory that is why HfO2 based MOS device are seems to me future devices. Pure form of HfO2, and its silicate are the potential candidate SiO2 as a gate material in a scaled down MOS technology. A continuous research and development (R&D) on this material is considerably seems to be more advanced compared to other high-k dielectrics (2\*/j!2z^^\_zDLLJaz\*\*!.z^z
^\_zECCJd^z
+.!+2!.\_zzz\$!+\*#z!0z(z\$/z+/!.2! zz/%#¥ nificant improvement in the performance of HfO2/SiO2z/0'z#0!z %!(!0.%z+\*zGw%z/1.¥ face (Cheong K.Y., 2007). Atomic layer deposition (ALD) is the most advisable and recommended process to deposit HfO2 (Cho M., 2002). However, large variations in growth rate, dielectric constant, and fixed charge are reported for HfO2 !,+/%0! z +\*z /%(%+\*z /1¥ strate. The interface stability is one of the most important issues in the deposition process. When HfO2 is considered to be deposited on SiC surface, the accurate knowledge of thermal stability at elevated temperatures is a must.
