US Patent 7821096 Semiconductor integrated circuit and system LSI including the same

A semiconductor integrated circuit having a diode element includes a diffusion layer which constitutes the anode and two diffusion layers which are provided on the left and right sides of the anode and which constitute the cathode, such that the anode and the cathode constitute the diode. A well contact is provided to surround both the diffusion layers of the anode and cathode. Distance tS between a longer side of the well contact and the diffusion layers of the cathode is shorter, while distance tL between a shorter side of the well contact and the diffusion layers of the anode and cathode is longer (tL>tS). Accordingly, the resistance value between the diffusion layer of the anode and the shorter side of the well contact is larger, so that the current from the diffusion layer of the anode is unlikely to flow toward the shorter side of the well contact. Thus, convergence of the current at the contact holes of the diffusion layer of the anode is reduced, so that the reliability of the diode element improves.