Base Resistance Controlled Thyristor Research Articles

Optimization of Design Parameters on Maximum Controllable Current of the Trench Gate Corrugated-base Base Resistance Controlled Thyristor

We investigated the maximum controllable current (MCC) characteristics of a base resistance controlled thyristor (BRT) entitled trench gate corrugated pbase BRT (TC-BRT), which suppresses the snapback effectively and increases the maximum controllable current considerably. Effects of design parameters of the TC-BRT on MCC such as the trench depth, the finger gate length, and the main gate length were investigated and the mechanism of the MCC was also investigated. Experimental results show that the MCC of the TC-BRT increased approximately 60% without sacrificing the on characteristics compared with the conventional BRT. The dominant factor, which increases the MCC of the TC-BRT, is a finger gate when the trench density is small. The effect of the trench on the MCC increases as the trench density and the trench depth increase.

CB-BRT: a new base resistance-controlled thyristor employing a self-aligned corrugated p-base

We propose and fabricate a new base resistance-controlled thyristor (BKT) employing a self-aligned corrugated p-base. The new device, entitled CB-BRT, suppresses the snap-back effectively and increases the maximum controllable current. Experimental results show that the snap-back of the CB-BRT is reduced significantly when compared with that of the conventional BRT. Also, the maximum controllable current of the CB-BRT increases as compared with the conventional BRT.

A 550 V Isolated Channel Base Resistance Controlled Thyristor (ICBRT)

In this paper we report a 550 V Isolated Channel Base Resistance Controlled Thyristor (ICBRT), which incorporates a heavily doped p-type diffusion at the edges of the p-base of the conventional Base Resistance Controlled Thyristor (BRT) to improve its turn-off capability. The desirable gate controlled turn-on and turn-off features of the BRT are retained in this new device along with separate turn-on and turn-off regions. A 70% improvement in the maximum controllable current density during resistive turn-off over the conventional BRT has been demonstrated in numerical simulations and experimental measurements.

Modelling the turn-off characteristics of the base resistance controlled thyristor (BRT)

An analytical model is described for the turn-off mechanism in the BRT. The assumptions which form the basis of the model are drawn from the results of two-dimensional numerical simulations of the turn-off process. It is shown that the device turns off when all the charge from the P-base is removed by the current flowing through the P-channel MOSFET into the diverter region. Based upon this, an expression has been derived for the time required for removal of the hole charge from the P-base (defined as the storage time). An expression for the maximum controllable current for the BRT (where it fails to turn off) has been derived by the condition that the storage time becomes infinite. The model predicts a decrease in the maximum controllable current with increase in the P-base sheet resistance and P MOS channel resistance. Based on the model, the maximum controllable current is shown to decrease with emitter width and increase, with emitter length. These predictions have been confirmed by experimental resistive load turn-off measurements on unit cell BRT devices. Consistent with the model, the measurements indicate no change in the controllable current with load voltages up to 500 V, indicating good RBSOA. The model has also been extended to calculate the holding current of the BRT and its dependence on device parameters.

An emitter switched thyristor with base resistance control

An MOS-gated emitter-switched thyristor structure with base resistance control, which combines the best features of both the emitter-switched thyristor (EST) and the base-resistance-controlled thyristor (BRT), is reported. With this structure, it is possible to obtain turn-off (dynamic) current densities above the static latch-up current density of the parasitic thyristor in the EST, while preserving its unique current saturation capability. It has been experimentally demonstrated for 600 V forward blocking devices that the maximum controllable current density under dynamic conditions is a function of both the gate bias and the dimensions of the N/sup +/ floating emitter. Turn-off measurements have demonstrated that the new structure has a maximum controllable current density of over 2.5 times that for the EST structure without base resistance control.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Trench-gate base-resistance-controlled thyristors (UMOS-BRTs)

Two base-resistance-controlled thyristor (BRT) structures with trench (UMOS) gate regions are described. A model for the maximum controllable current density for these devices is proposed and demonstrated to agree well with experimental results obtained on devices with 600-V forward-blocking capability. >

Theoretical and experimental characteristics of the base resistance controlled thyristor (BRT)

Described are the characteristics of a new MOS gated thyristor structure called the base resistance controlled thyristor (BRT), in which the turn-off of a thyristor built with an N drift region is achieved by reducing the resistance of the p-base region under MOS gate control. A p-channel MOSFET used to achieve turn-off is formed in the N drift region. The device is designed so that, when the p-channel MOSFET is switched on, holes are diverted from the p-base region of the thyristor into the adjacent p/sup +/ region, raising the holding current of the thyristor above the operating current level, and turning off the thyristor. Results of extensive 2-D numerical simulations that have been performed to demonstrate operation of this new device concept are discussed. Experimental results on 600-V devices fabricated with an IGBT process have corroborated theoretical predictions. Current densities above 900 A/cm/sup 2/ have been turned off at room temperature with a gate bias of -10 V.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A new MOS-gated power thyristor structure with turn-off achieved by controlling the base resistance

A new MOS-gated power thyristor structure, called the base-resistance-controlled thyristor (BRT), is described. In this structure, the turn-off of a thyristor with an N-drift region is achieved by reducing the resistance of the P-base region under MOS-gate control. In contrast with previous devices, a P-channel MOSFET integrated in the N-drift region is used for this purpose. It has been shown, by two-dimensional numerical simulations and experimental measurements on devices fabricated using a seven-mask process, that devices with 600-V forward blocking capabilities can be achieved with a forward drop close to that for a thyristor. The ability to turn off the thyristor current flow has been verified over a broad range of current densities.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>