Thyristor Physics

1 Device basics. - 1. 1 Introduction. - 1. 2 SCR current-voltage characteristics. - 1. 3 Basic SCR construction features. - 1. 4 Gate triggering. - 1. 5 Holding current. - 1. 6 Triggering a shorted emitter SCR. - 2 Current Gain. - 2. 1 Variation of current gain with current. - 2. 2 Current gain measurement. - 3 Thyristor Maximum Voltage Blocking Capability. - 3. 1 Introduction. - 3. 2 Maximum forward-blocking capability VBO. - 3. 3 Maximum reverse-blocking capability. - 3. 4 The punch-through condition. - 3. 5 Temperature dependence. - 3. 6 Surface breakdown. - 3. 7 Reverse-conducting thyristor. - 4 Some High-Injection-Level Effects. - 4. 1 Introduction. - 4. 2 Ambipolar mobility and diffusivity. - 4. 3 Mobility and diffusivity versus current density. - 4. 4 Lifetime at high injection levels. - 4. 5 High-low junctions at high current densities. - 4. 6 Current gain fall-off. - 5 The Gate-Triggered SCR Turn-On Transient. - 5. 1 Introduction. - 5. 2 Charge-control model of a bipolar transistor. - 5. 3 Charge-control model of a p-n-p-n structure. - 5. 4 Delay time. - 5. 5 Rise time with a resistive load. - 5. 6 Rise time with inductive load. - 5. 7 Propagation of the on state. - 6 The Nongated Undesirable Thyristor Triggering. - 6. 1 Introduction. - 6. 2 Thermal turn on. - 6. 3 Light triggering. - 6. 4 Voltage triggering. - 7 Thyristor Voltage Drop in the On State. - 7. 1 Introduction. - 7. 2 Herlet's closed-form p-i-n diode analysis. - 7. 3 Kokosa's numerical analysis. - 7. 4 Numerical analysis of Cornu and Lietz. - 7. 5 Otsuka's forward-drop analysis. - 8 SCR Turn-off Transient. - 8. 1 Introduction. - 8. 2 Storage time ts1. - 8. 3 Fall time tf1. - 8. 4 Storage time ts2. - 8. 5 Fall time tf2. - 8. 6 Effect of the gate current. - 8. 7 Simplified approaches. - 8. 8 Experimental data. - 9 Gate Turn-off Thyristor (GTO). - 9. 1 Introduction. - 9. 2 Plasma-pinchingmechanism. - 9. 3 Turn-off velocity. - 9. 4 Pinching (focusing) time and turn-off gain. - 9. 5 Maximum anode and gate currents. - 9. 6 Plasma-pinching in the ungated n base. - 9. 7 Theoretical model compared with experiment. - 10 Thyristor di/dt and Current Pulse Capability. - 10. 1 Introduction. - 10. 2 Test circuit for gate-triggered di/dt. - 10. 3 Initial turn-on region. - 10. 4 di/dt capability of the gated and nongated turn on. - 10. 5 Localized temperature rise for a short single pulse. - 10. 5 Temperature rise for long or recurrent pulses. - 10. 7 Temperature rise and transient thermal impedance during turn-on spreading. - 10. 8 Methods of increasing the initial turn-on area. - 10. 9 Emitter gate. - 10. 10 Emitter shorts versus the turn-on time. - 10. 11 Beam-fired thyristor. - 10. 12 Field-controlled thyristor. - 11 Bidirectional p-n-p-n Switches. - 11. 1 Introduction. - 11. 2 Bidirectional p-n-p-n diode switch. - 11. 3 Current distribution across a forward-biased junction bounded by resistive layers (current-crowding effect). - 11. 4 Junction gate. - 11. 5 Remote gate. - 11. 6 Triac. - 12 Commutation of Triacs. - 12. 1 Introduction. - 12. 2 Current and voltage waveforms during commutation. - 12. 3 Role of stored charges in triac commutation. - 12 A Recovery of a p+ -n abrupt-junction diode. - 12. 5 Snubber networks for dv/dt suppression. - 13 Silicon Surface. - 13. 1 Introduction. - 13. 2 Ideal MOS diode. - 13. 3 Silicon surf ace states and charges. - 14 Avalanche Breakdown Enhancement by Mesa Contouring. - 14. 1 Introduction. - 14. 2 Positive and negative bevel angles. - 14. 3 Theoretical approach to the field computation in the depletion region. - 14. 4 Negative bevel angle. - 14. 5 Positively beveled junctions. - 14. 6 Novel approaches to beveling. - 15 Planar-Junction Avalanche Breakdown Improvement. - 15. 1 Introduction. - 15. 2 Diffused guard ring. - 15. 3 Junction field plate annular ring and channel stopper. - 15. 4 Resistive field plate. - 15. 5 p-n junction with field limiting rings. - 15. 6 Etch-contoured planar junctions. - 16 Thyristor Thermal Response. - 16. 1 Introduction. - 16. 2 Heat generation and absorption in the forward-biased thyristor. - 16. 3 Determination of junction temperature. - 16. 4 Generalized concept of thermal impedance. - 16. 5 Device temperature response to an arbitrary power waveshape. - 16. 6 Thyristor thermal impedance measurement. - 16. 7 Computer-aided thermal analysis. - 17 Thyristor Circuits Basics. - 17. 1 Introduction. - 17. 2 SCR and triac control and triggering methods. - 17. 3 Thyristor triggering devices. - 17. 4 Commutation. - 17. 5 Effect of an impedance between the gate and cathode of a thyristor. - 17. 6 Thyristor protection circuits. - 17. 7 Some thyristor applications. Language: English