Formation of hafnium-aluminum-oxide gate dielectric using single cocktail liquid source in MOCVD process

We demonstrate that a high quality metal organic chemical vapor deposition (MOCVD) HfAl/sub x/O/sub y/ (hereafter HfAlO) dielectric film can successfully be deposited with a wide range of composition controllability between HfO/sub 2/ and Al/sub 2/O/sub 3/ in HfAlO using a single cocktail liquid source HfAl(MMP)/sub 2/(OiPr)/sub 5/. A composition ratio between 45 to 90% of HfO/sub 2/ in HfAlO is achieved by controlling deposition process parameters. The effect of the composition ratio between HfO/sub 2/ and Al/sub 2/O/sub 3/ on the electrical properties of the film is also investigated. The HfAlO film with 90% HfO/sub 2/ (10% Al/sub 2/O/sub 3/), which has minimum sacrifice of K value (around 19), shows a great improvement in thermal stability and significant reduction of interfacial layer growth during subsequent thermal processes, leading to the reduction in leakage current by around 2 orders of magnitude compared to pure HfO/sub 2/ film. The HfAlO film also shows good compatibility with TaN metal gate electrode under high temperature annealing process.