Design of field limiting ring employing trench structure for high power devices

Abstract

Excellent voltage blocking capability and reliability can be obtained by trenching the field-limiting ring site which would be implanted. The trench etch step makes the junction depth deeper so that junction curvature effect and surface breakdown are less happened. The numerical analyses reveal two facts that the trenched field limiting ring has smaller maximum electric field and the electric field peak is deeper from the substrate surface, hence silicon dioxide layer can be protected. Therefore the voltage blocking capability and reliability of the new structure can be improved. The simulated results show that the trenched field limiting ring can have smaller critical electric field and accomplish near 30% increase of breakdown voltage in comparison with the conventional structure.