Analysis of Influence to Gate Stack of Eeprom Using CL Doped Re-Oxidation

Chlorine doped oxidation by adding chloride from HCl or C2HCl2 (DCE) in oxidation process can improve SiO
2
quality. The process will lead to chloride-rich zone near the Si-SiO
2
interface and bond with dangling Si, which reduces the density of interface charge. In this paper, the different ratio of chloride doped of oxidation by test wafer with pre-Oxide to simulate the process flow of 18um EEPROM is applied to observe and compare the re-oxidation rate and charge change of the final Oxide. The device performance of threshold voltage and breakdown voltage are also observed by 18um EEPROM test vehicle. According to the experimental results of test wafer, as the increase of DCE ratio, the re-oxidation rate and charge first decrease but tends to be flat. When applied to 18um EEPROM, the phenomenon of threshold voltage and breakdown voltage increase at first and slow down, which is match with the result in control wafer.