| 摘要 |
PURPOSE:To obtain a Triac, voltage thereof hardly drops under the state of turn-ON and which has large resistance of a change with time on turn-OFF, by joining P-N-P-N-P or N-P-N-P-N five semiconductor layers in succesion, fitting electrode terminals to the semiconductor layers at both ends and generating photocurrents in P-N junctions, to which reverse bias voltage is being applied, by the projection of beams. CONSTITUTION:P-N-P-N-P five layers are formed in a bilaterally symmetrical manner. That is, two N type regions 2 and 3 are shaped in a P<-> type Si substrate 1, and P<+> type regions 4 and 5 are each diffused and formed in the regions 2 and 3. Electrode terminals (a) and (b) are connected to the regions 4 and 5 and reverse bias voltage is applied, and P-N junctions generated among each layer are irradiated with beams of generate photocurrents. Consequently, an equivalent circuit for the device can be regarded as the coupling of three transistors Tr1, Tr2, Tr3, and the current amplification factor of Tr1 is made smaller than that of Tr2. Accordingly, discharge currents are reduced, use in high frequency is also enabled, and characteristics on a turn are improved. |
