Lateral Insulated-gate Bipolar Transistor Structure Research Articles

A Study on 4H-SiC LIGBT with Dual Emitter for High Voltage Driver IC

This paper describes a lateral insulated gate bipolar transistor (LIGBT) with dual emitter structure in 4H-silicon carbide (4H-SiC). The electrical characteristics of the dual-emitter LIGBT are better than those of the conventional 4H-SiC LIGBT. The dual-emitter structure has an additional emitter between the emitter and the collector in the conventional LIGBT structure. The addition of the emitter can significantly improve forward voltage drop, on-resistance and current driving characteristics. Experimental results show that the 4H-SiC dual-emitter LIGBT has lower forward voltage drop, lower on-resistance and a higher current driving capability than the conventional 4H-SiC LIGBT.

LIGBT-based ESD Protection Device with High Holding Voltage for 15 V Power IC Applications

In this study, a lateral insulated-gate bipolar transistor (LIGBT)-based device for electrostatic discharge (ESD) protection of 15 V power IC applications is proposed. This new ESD surge protection device has a floating N+ region inserted into the N-well of the conventional LIGBT structure, allowing for low trigger voltages, high holding voltages, high ESD robustness, and high latch-up immunity. The influence of the length of the N+ floating region on the electrical performance of the LIGBT-based protection device was characterized and optimized using transmission line pulsing (TLP) and transient induced latch-up (TLU) tests. A LIGBTbased protection device with a trigger voltage of 20.2 V and a holding voltage of 16.2 V was fabricated. Electrostatic discharge tests using the human body model (HBM) and the machine model (MM) show that the new device exceeds existing commercial ESD sensitivity standards. Moreover, the LIGBT device passed reliability testing over the temperature range of 300K to 500K. Therefore, the proposed LIGBTbased ESD protection device has a high holding voltage and high latch-up immunity suitable for 15 V power IC applications.

Simulation Study of a High-Current and Fast Dual-Gate IGBT Device With High-<inline-formula> <tex-math notation="LaTeX">$K$ </tex-math> </inline-formula> Material

We propose a novel method to turn OFF the lateral insulated gate bipolar transistor (LIGBT) device. Contrary to the conventional means, we improve the LIGBT switching speed by boosting the carrier density in the drift region. With the introduction of a high-permittivity material (HK) into a novel LIGBT structure, a parasitic pMOS with an HK dielectric is formed. The electric field from the pMOS source to the gate introduces many more holes into the drift region of the LIGBT, which significantly increases the device current in the ON-state. When the device is about to be turned OFF, extra electrons are rapidly neutralized by the holes in the channel of the pMOS during the transition period. Then, the device is immediately switched OFF through voltage coupling from the pMOS gate. The switching-OFF time of the proposed LIGBT is only limited by the external gate-driving circuit, which can be as short as 5 ns and is almost free of the tail current according to a numerical simulation.

A New Lateral-IGBT Structure With a Wider Safe Operating Area

A new lateral insulated gate bipolar transistor (LIGBT) for junction-isolated technologies is presented. The nLIGBT is integrated in an existing smart power technology without changing any process layers. The technology has a 0.35-mum CMOS core and is extended with five process layers in order to handle up to 80 V. The drift region of the nLIGBT is completely surrounded by p+ regions, creating a very effective hole bypass or diverter structure. This yields an LIGBT with a very wide safe operating area. The device has a breakdown voltage of 75 V and is able to operate up to 47 V (dc) when the gate is fully open. Furthermore, this device turns off without current tail, resulting in extremely fast turn-off times, which are solely determined by the voltage-rise phase. A true competitor for the quasi-vertical n-type drain extended metal oxide semiconductor (nDEMOS) in this technology is created

Electrothermal model for an SOI-based LIGBT

Several vertical insulated gate bipolar transistor (IGBT) electrothermal models are currently available on circuit simulators. However, no reliable electrothermal models have been proposed for the lateral IGBT (LIGBT). In this paper, for the first time, an electrothermal model for an LIGBT structure based on a novel concept recently reported by Udrea (IEDM, p. 451, 2004), and here termed silicon-on-membrane, is presented. The model relies on a systematic study of both the isothermal and self-heating behaviors of the device. The model is further implemented in the SPICE circuit simulator language and validated against extensive Medici numerical simulations and experimental data

A new LIGBT structure to suppress substrate currents in a junction isolated technology

In this paper, a new lateral insulated gate bipolar transistor (LIGBT) structure is proposed to suppress substrate currents in a junction isolated technology by using two buried layers on top of each other. This structure not only allows to reduce the substrate to anode current ratio to less than 10 −7, it also yields a device with a large safe operating area and a fast turn-off. Because of the two buried layers, the proposed LIGBT can be used as a floating (above substrate potential) device. Furthermore, the LIGBT is introduced in an existing 80 V smart power technology without the costly need of defining new layers. It has also been shown that the proposed LIGBT can compete with vertical DMOS (VDMOS) devices when used as a large driver. Together with an equivalent circuit, two dimensional simulation has been used to explain the observed device’s substrate current behaviour.

A New Silicon-on-Insulator Lateral Insulated-Gate Bipolar Transistor with Dual-Channel Structure

To improve the latch-up and forward voltage drop properties of the silicon-on-insulator (SOI) lateral insulated-gate bipolar transistor (LIGBT), a new SOI LIGBT structure is proposed and fabricated. The new device employs a dual-channel structure in order to enable more electrons to flow into the n-drift layer and to improve the latch-up characteristic.

Dynamic latch-up in advanced LIGBT structures at high operating temperatures

Abstract The dynamic latch-up process in conventional and modified lateral insulated gate bipolar transistor (LIGBT) structures is studied in this paper. In a previous study, we have argued that the modified structure shows a superior static latch-up performance at high operating temperatures. The dynamic latch-up has also been measured under resistive load at different operating temperatures. The dependence of the dynamic latch-up current with the gate resistance has also been taken into account. A figure of merit of the dynamic latch-up current normalized to the static latch-up current level as a function of operating temperature shows the excellent electrical behaviour of the proposed modified LIGBT structure at high temperatures when compared with its conventional counterpart.

Electrical characteristics of advanced lateral insulated-gate bipolar transistor structures at 77 K

Abstract The electrical characteristics of advanced 360 V lateral insulated-gate bipolar transistor (LIGBT) structures operating at cryogenic temperatures are analysed in this paper. Detailed performed static and dynamic measurements on ceramic packaged LIGBT structures at 77 K are provided. A reduction of the breakdown voltage, the leakage current, the turn-off time and the transient losses has been observed when decreasing the operating temperature. A reduction of 70% of the turn-off time and a 45% of switching losses can be obtained when lowering the temperature from 300 to 77 K. At high current density levels, the on-state voltage drop of the conventional LIGBT structure increases with temperature. On the contrary, on-state voltage drop of an advanced modified LIGBT structure increases when the temperature is reduced.

Lateral insulated gate bipolar transistor (LIGBT) structure based on partial isolation SOI technology

A new LIGBT structure based on partial isolation SOI technology is proposed and demonstrated through numerical simulations. In comparison with conventional SOI LIGBTs, the new structure offers an enhanced RESURF (REduced SURface Field) effect and improved heat dissipation with no compromise in the switching speed and on-state resistance.

The modified structure of the lateral IGBT on the SOI wafer for improving the dynamic latch-up characteristics

The modified structure of the lateral IGBT(LIGBT) on an SOI wafer for improving the dynamic latch-up characteristics is presented together with its numerical simulations and experimental results. The modified LIGBT structure has a p/sup +/-emitter layer between the collector and gate regions. The current at which the latch-up occurs during the turn-off transient under an inductive load is estimated in comparison with that of the conventional LIGBT. The dynamic latch-up current at room temperature and 125/spl deg/C for the modified LIGBT were 350 A/cm/sup 2/ and 290 A/cm/sup 2/, respectively. These results indicate the improvement of about 3.5 times at room temperature and about 5.5 times at 125/spl deg/C compared with those for the conventional LIGBT. This remarkable improvement in the dynamic latch-up performance is accomplished at the expense of an increase of 0.8 V in the forward voltage drop.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Analysis and characterization of the segmented anode LIGBT

A LIGBT (lateral insulated gate bipolar transistor) structure, called the segmented-anode LIGBT, is presented and analyzed. The anode structure responsible for the injection of minority carriers for conductivity modulation is implemented using segments of p/sup +/ and n/sup +/ diffusion along the device width. This minimizes the forward bias of the p/sup +/ injector during device turn-off, resulting in higher switching speed compared to the shorted-anode LIGBT. Since the n/sup +/ region required for electron extraction is implemented along the device width and consumes only a small amount of area, a reduction in device size is also achieved. The switching speed and reduced device size result in better tradeoff between on-resistance and turn-off time compared with other LIGBTs. Two-dimensional numerical simulations are carried out to demonstrate the operation and characteristics of the structure, and the experimental inductive and resistive switching characteristics of the structure are discussed.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Analysis of new lateral insulated gate bipolar transistor structures for power applications

This paper aims to describe the physical behaviour of different lateral insulated gate bipolar transistor (LIGBT) structures. It reviews a variety of LIGBTs and a new modification of the basic LIGBT structure consisting of a buried layer, an auxiliary cathode and a highly doped sinker between the MOS channel and the auxiliary cathode. Results from two-dimensional numerical simulations show an improvement in the device current in comparison with other LIGBT structures.