A Novel Conformal Thick Oxide Technology for On-Chip High-Voltage Isolation

Abstract

In this letter, a novel conformal thick oxide technology is proposed and demonstrated for on-chip high-voltage isolation. The proposed technology utilizes alternate deposition and oxidation of polysilicon to form thick high-quality conformal oxide with a reasonable process time. Experimental results show that breakdown voltages (BVs) as high as 4.19 kV can be achieved with double-side, 6-<inline-formula> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula>-thick planar oxide layers formed using this technology. Excellent conformity was also observed inside deep silicon trenches. The double-side, silicon-embedded transformer (DSSET) fabricated using this isolation layer technology achieved an isolation capability of 1.84 kV.