| 摘要 |
PURPOSE:To improve a critical OFF voltage increase rate (dv/dt)M of a lateral photo silicon controlled rectifier (SCR) by making large hFE of pnp element and photo sensitivity by thermal treatment, making small a gate resistance and by integrating elements in the same chip. CONSTITUTION:Response of pnp element of photo SCR delays when hFE is made large, and when a gate resistance is RG, a gate voltage VG CRGXdv/dt, and RG is made small, a critical off voltage increase rate becomes large. Meanwhile, a displacement current by dv/dt is a transient phenomenon and therefore (dv/dt)M can be improved remarkably by making large hFE and small RG by a mutual reinforcing effect by these two effects. When hFE is increased by making longer the life time of base layer, a photo sensitivity is generally enhanced, while the minimum trigger current reduces a little and the (dv/dt)M is improved. Such photo sensitivity is improved by about 30% through annealing under the N2 atmosphere at 900 deg.C. A value of dv/dt can be improved by about three times as compared with that when a resistance is externally provided by forming the RG with the P layer 9 in the N type substrate 1 and connecting the one end thereof to the gate 3 while the other end to the cathode 8 through the electrode 10. |
