An Isolation Structure Applying Potential Control Technique for 1200 V HVICs

The potential control technique is realized for 1200 V isolation structure by potential delivering field plates (PDFPs). The PDFPs are uniformly spaced on the high voltage junction termination (HVJT) region, change their own spacings across the P-isolation ring region, and extend to the P/N-channel lateral diffused MOS (P/NLDMOS) with widened spacing nearby the source/drain side and narrowed spacing on the middle region of drift. The surface potentials from the HVJT can be delivered to the lateral diffused MOSFET (LDMOS) regions by PDFPs, modulating the surface potential profile and suppressing premature leakage. The experimental results indicate that the proposed isolation structure has a 364% improvement in breakdown voltage (BV) compared with the isolation structure without PDFPs.