Design of novel DDSCR with embedded PNP structure for ESD protection**Project supported by the Fundamental Research Funds for the Central Universities (No. JUSRP51323B), the Joint Innovation Project of Jiangsu Province (No. BY2013015-19), the Summit of the Six Top Talents Program of Jiangsu Province (No. DZXX-053), and the Graduate Student Innovation Program for Universities of Jiangsu Province (Nos. KYLX_1119, SJZZ_0148).

Abstract

A novel dual-directional silicon controlled rectifier (DDSCR) device with embedded PNP structure (DDSCR-PNP) is proposed for electrostatic discharge (ESD) protection, which has greatly reduced latch-up risk owing to the improved holding voltage (Vh). Firstly, the working mechanism of the DDSCR-PNP is analyzed. The theoretical analysis indicates that the proposed device possesses good voltage clamp ability due to the embedded PNP (PNP_2). Then, experimental devices are fabricated in a 0.35 μm bipolar-CMOS-DMOS process and measured with a Barth 4002 transmission line pulse testing system. The results show that the Vh of DDSCR-PNP is much higher than that of the conventional DDSCR, and can be further increased by adjusting the P well width. However, the reduced leakage current (IL) of the DDSCR-PNP shows obvious fluctuations when the P well width is increased to more than 12 μm. Finally, the factors influencing Vh and IL are investigated by Sentaurus simulations. The results verify that the lateral PNP_2 helps to increase Vh and decrease IL. When the P well width is further increased, the effect of the lateral PNP_2 is weakened, causing an increased IL. The proposed DDSCR-PNP provides an effective and attractive ESD protection solution for high-voltage integrated circuits.