EFFECTS OF OXIDATION PROCESS ON INTERFACE ROUGHNESS OF GATE OXIDES ONSILICON - X-RAY REFLECTIVITY STUDY

We report on the effects of the wet and dry oxidation processes on the interfacial roughness and time dependent dielectric breakdown (TDDB) characteristics of the poly-Si/SiO2/Si(100) trilayer. The interface ro ughness of the oxide layers buried under a thick poly-Si electrode has been investigated using an x-ray reflectivity technique. Analysis of x-ray reflectivity data for the trilayer samples and for a bare oxide film shows that interface roughness of poly-Si electrode/SiO2 interfac es depends on oxidation process while oxide layers have smooth SiO2/Si -subtstrate interfaces. TDDB of the SiO2 layer has also been observed to depend on the oxidation process, indicating that the interface roug hness is a crucial factor affecting the TDDB characteristics. The wet oxidized SiO2 film is more stable to dielectric breakdown and has smoo ther interfaces than the dry oxidized sample. (C) 1998 American Instit ute of Physics.