S. Huang

Analysis of SEB and SEGR in super-junction MOSFETs

The electric field distribution in the super-junction power MOSFET is analyzed using analytical modeling and numerical simulations in this paper. The single-event burnout (SEB) and single-event gate rupture (SEGR) phenomena in this device are studied in detail. It is demonstrated that the super-junction device is much less sensitive to SEB and SEGR compared to the standard power MOSFET. The physical mechanism is explained.

The injection efficiency controlled IGBT

An IGBT structure in which the anode injection efficiency changes with current density, the injection efficiency controlled IGBT (EEC-IGBT), is proposed. The anode injection efficiency of the IEC-IGBT is controlled via a current sensor inherent in its structure. Anode injection efficiency is strongly enhanced at low device current density and significantly reduced at high device current density. This enables the device to have a low on-state voltage drop (V/sub on/) and superior safe operation area (SOA), making it very suitable for high-power applications. Simulation results based on 3.3 KV DMOS NPT devices indicate the on-state voltage drop of the IEC-IGBT is reduced by 0.6 V (20%) and the short-circuit SOA (SCSOA) is improved by several times compared to the conventional IGBT.

A dynamic n-buffer insulated gate bipolar transistor

Abstract A novel dynamic n-buffer insulated gate bipolar transistor (DB-IGBT) with double gates is proposed and analysed in detail by using two-dimensional numerical simulations. It is found that the turn-off energy loss of this device is reduced and the short-circuit performance is improved significantly compared to the optimised conventional IGBT. Similar to the NPT-IGBT, the switching performance of the DB-IGBT is insensitive to temperature. These advantages make this device an attractive candidate for high frequency high power application.

An experimental and numerical investigation of IGBT blocking characteristics

The breakdown characteristics of 600 V DMOS IGBT are investigated in detail using both experimental results and numerical simulations with self-heating effects included. The blocking characteristics of 1.8 kV trench IGBT are also studied. It is shown that thermally assisted impact ionization causes the IGBT device to breakdown. A negative resistance region of breakdown curve is observed, and the increased bipolar current gain results in more significant negative resistance part for the PT device. With negative charge introduced into the gate oxide, the breakdown characteristics of the trench IGBT can be improved.

1.4 kV, 25 A, PT and NPT trench IGBTs with optimum forward characteristics

In this paper, we report the development of 1.4 kV 25 A punch-through (PT) and nonpunch-through (NPT) trench IGBTs with ultra-low on-resistance, latch-up free operation and highly superior overall performance when compared to previously reported DMOS IGBTs in the same class. We have fabricated both PT and transparent anode NPT devices to cover a wide range of applications which require very low on-state losses or very fast time with ultra-low switching losses. The minimum forward voltage drop at the standard current density of 100 A/cm/sup 2/ was 1.1 V for PT nonirradiated devices and 2.1 V for 16 MRad PT irradiated devices. The nonirradiated transparent emitter NPT structure has a typical forward voltage drop of 2.2 V, a turn-off time below 100 ns and turn-off energy losses of 11.2 mW/cm/sup 2/ at 125 C. The maximum controllable current density was in excess of 1000 A/cm/sup 2/.

A comparative investigation of the MCST with MCT and IGBT

Abstract In this paper the characteristics of the single gate MOS controlled current saturation thyristor (MCST) is investigated in comparison with the MCT and IGBT. In the on-state the MCST operates in the thyristor-like mode at low anode voltage and enters the IGBT-like mode automatically with increasing anode voltage. It offers a low on-state voltage drop and current saturation capability. A simplified analytical model for the on-state is presented. The saturation current density of the MCST is strongly dependent on the ratio of the p + buffer doping to the n-well doping, i.e., α pnp2 / α npn , and drops with increasing temperature, leading to its excellent safe operating area and making it suitable for high power applications.

A novel single gate MOS controlled current saturated thyristor

A novel single gate MOS controlled current saturation thyristor (MCST) device is proposed. In the on-state the MCST operates in thyristor-like mode at low anode voltage and enters the IGBT-like mode automatically with increasing anode voltage, offering a low on-state voltage drop and current saturation capability. Simulation results based on 6.5 kV trench devices indicate the turn-off energy loss of the MCST is reduced by over 35% compared to the IGBT. The saturation current density of the MCST is strongly dependent on the on-set voltage of the p/sup +/ buffer/n-well junction, leading to its excellent safe operation area (SOA) and making it suitable for high power applications.

The quasi-punch-through structure for power semiconductor devices

A new concept named quasi-punch-through (QPT) structure is proposed for power semiconductor devices in this paper and is found to possess the advantages of both PT and NPT structures. The structure utilizes closely located trenches at the anode end of the base to act as an electric-field shielding layer. With this structure, the highly doped N buffer layer can be avoided and the base thickness is kept low for a superior trade-off between the on-state voltage and turn-off loss. It is also found that, like NPT power devices, such devices have temperature insensitive turn-off losses and hence are able to be used at higher junction temperatures under high-frequency operating conditions.

A new single gate MOS controlled thyristor with current saturation and large SOA

A novel single gate MOS controlled current saturation thyristor (MCST) device is proposed. In the on-state the MCST operates in thyristor-like mode at low anode voltage and enters the IGBT-like mode automatically with increasing anode voltage, offering a low on-state voltage drop and current saturation capability. The saturation current density of the MCST is strongly dependent on the on-set voltage or the p+ buffer/n-well junction, leading to its excellent safe operation area (SOA) and making it suitable for high power applications.

A dual-channel IEGT

A Dual Channel Injection Enhanced Gate Transistor (DC-IEGT) device structure which allows for an additional p-channel to collect holes during turn-off is proposed and analysed in detail by extensive two-dimensional simulations. The DC-IEGT shows overall superior performance over the conventional IEGT and IGBT and is characterised by low on-state voltage drop, fast switching and large SOA.