N. Luther-King

Comparison of Trench Gate IGBT and CIGBT Devices for Increasing the Power Density From High Power Modules

Recently much research has been focused on increasing the functionality and output power density per unit area in power electronic modules without increasing board space. In high power applications, MOS-controlled devices with trench gates are the most desirable as their reduced V ce(sat) enables increased conduction current density. However, with increased drift region thickness, there is significant increase in conduction loss in trench gate-insulated gate bipolar transistor (T-IGBT) due to low plasma density from inherent p-n-p transistor action. In comparison, a well-designed MOS-controlled thyristor structure such as the trench-clustered insulated gate bipolar transistor (T-CIGBT), can provide low on-state conduction loss with gate voltage turn-on and turn-off. The comparison of 3.3 kV/800 A simulation results presented in this paper shows that the T-CIGBT is a superior candidate over TIGBT to increase the power density from existing high-voltage IGBT module footprints.

Experimental Demonstration of 3.3kV Planar CIGBT In NPT Technology

Due to the desirable properties of MOS-gate control, low conduction losses at high voltages, MOS-controiled thyristor structures are preferred for applications at 3.3 kV and beyond. In this paper, we report the results of the first experimental demonstration of the 3.3 kV rated CIGBT (Clustered Insulated Gate Bipolar Transistor) with planar gates in NPT technology. CIGBT is a three terminal MOS- controlled thyristor. Our results show that, with a positive Vce(sat) temperature coefficient and for identical turn-off loss, its Vce(sat) can be more than 0.7 V lower than that of an IGBT. Moreover, for the same gate voltage, it is shown that CIGBT shows lower saturation current density compared to the IGBT. Additionally, due to controlled thyristor mode of operation, a more favourable trade-off performance can be obtained using lower anode implant doses without significantly compromising Vce(sat).

Numerical Evaluation of the Short-Circuit Performance of 3.3-kV CIGBT in Field-Stop Technology

In this paper, the short-circuit performance of a conventional 3.3-kV clustered insulated gate bipolar transistor (CIGBT) in field-stop (FS) technology is evaluated through extensive 2-D numerical simulations. For comparison, an equivalent 3.3-kV FS IGBT is considered. The conventional CIGBT shows superior performance of lower on-state voltage drop and saturation current densities in comparison to an equivalent IGBT. Further improvements to the CIGBT performance can be obtained without sacrificing on-state voltage drop by using a PMOS trench gate. The charge balance and electric field distribution with the varying n-buffer thickness at short-circuit condition are analyzed in detail.

Performance of a trench pmos gated, planar, 1.2 kV Clustered insulated gate bipolar transistor in NPT technology

The conventional Clustered IGBT is a MOS controlled power device with controlled thyristor action, which has been demonstrated to show lower Vce(sat) compared to IGBT, current saturation characteristics at high gate voltages and short circuit performance. In this paper, we show that, with the incorporation additional PMOS trench gates in a normally planar gate structure, the performance of the device can be enhanced even further to tailor saturation current levels and hence improve short-circuit performance without degrading Vce(sat). This is evaluatated using 1.2kV planar NPT CIGBT through extensive 2D simulations. This is the first paper to demonstrate a simple mechanism to control the saturation current without degrading Vce(sat) and other characteristics.

Clustered Insulated Gate Bipolar Transistor in the Super Junction Concept: The SJ-TCIGBT

We report results of comprehensive 2-D simulation evaluation of the first MOS-controlled thyristor structure employing the super junction concept on a 1.2-kV field stop structure. In comparison to a standard device, simultaneous reduction in Vce(sat) and Eoff can be achieved in a super junction trench clustered insulated gate bipolar transistor (SJ-TCIGBT). The simulation results show that up to 80% reduction in Eoff is possible. Unlike the super junction insulated gate bipolar transistors, there is no significant increase in the saturation current with the anode voltage or the depth of the pillars. SJ-TCIGBT is a highly promising next generation device concept with record-breaking Vce(sat)-Eoff tradeoff enhancement to improve converter efficiency.

Performance Evaluation of 3.3-kV Planar CIGBT in the NPT Technology With RTA Anode

In this paper, we report the experimental results of a 3.3-kV-rated clustered insulated gate bipolar transistor (CIGBT) with planar gates in nonpunchthrough technology (NPT) and rapid thermal annealing (RTA) anode. Previously, it had been shown that, for identical turn-off losses, the on -state voltage of the 3.3-kV CIGBT is more than 0.7 V lower than that of an equivalent IGBT. Herein, we show that, due to the low saturation current density, the CIGBT has a rugged short-circuit performance of more than 10 μs even at 125 °C. Furthermore, results also show that the use of the RTA anode, as compared with, the diffused anode helps in reducing the turn-off losses by about 50% without affecting the Vce(sat) value of the device.

Evaluation of 1.2kV Super Junction trench-gate clustered insulated gate bipolar transistor (SJ-TCIGBT)

We report, for the first time, results of extensive 2D simulation evaluation of the first MOS controlled thyristor structure employing the Super Junction concept on a 1.2 kV field stop structure. In comparison to a standard device, simultaneous reduction in Vce(sat) and Eoff can be achieved in a Super Junction Trench Clustered Insulated Gate Bipolar Transistor (SJ-TCIGBT). The simulation results show that up to 80% reduction in Eoff is possible. Unlike the Super Junction Insulated Gate Bipolar Transistors, there is no significant increase in the saturation current with the anode voltage or the depth of the pillars. SJ-TCIGBT is a highly promising next generation device concept with record-breaking Vce(sat) — Eoff trade-off enhancement to improve converter efficiency.