A novel high-voltage interconnection structure with dual trenches for 500V SOI-LIGBT

A novel high-voltage interconnection (HVI) structure with dual trenches for 500V SOI-LIGBT is proposed in this paper. Compared with the conventional dual trenches structure, the proposed structure features a shallow trench (T₁) and a deep trench (T₂) beneath the HVI. By employing the shallow trench (T₁), the potential can easily penetrate into the deep trench (T₂) and the total potential sustained by the dual trenches (T₁ and T₂) is increased. The experimental results demonstrate that the proposed dual trenches structure can fully shield the influence of HVI with significant reduction in the area of the HVI region. With almost the same breakdown voltage of 550V as the conventional dual trenches structure, the length of the silicon region between the active region and the dual trenches in the proposed structure is shortened from 45um to 15um. The area of the HVI region is shrunk by 57% in comparison to the conventional dual trenches structure.