Advantages of HfAlON gate dielectric film for advanced low power CMOS application

There are a number of challenges against an actual employment of high-k films in the production, but ultra-thin SiON films cannot survive for low power application anymore. On the other hand, any new materials introduced into ULSI fabrication processes are required to be used for a couple of device generations, so the material selection should be carefully made. We have investigated HfAlON film as a high-k material in perspective of the equivalent oxide thickness (EOT) = 1nm, and has newly developed a layer-by-layer deposition and annealing (LL-D&A) method for the film growth technique and a high temperature oxygen annealing (HiTOA) for the post-deposition annealing process, in order to overcome intrinsic challenges of deposited films. This paper describes recent progress of HfAlON gate stack technology, and discusses advantages of those approaches for advanced low power CMOS from scalability viewpoints of material and film growth technique as well as from experimental results of gate leakage current reduction, mobility improvement and threshold voltage control.