An article about IGBT chips/application fields

IGBT (Insulated Gate Bipolar Transistor) is a composite fully-controlled-voltage-driven-power semiconductor device composed of BJT (Bipolar Junction Transistor) and MOS (Insulated Gate Field Effect Transistor), which has self-off break feature. Simply put, it is a non-on or off switch. The IGBT has no function of amplifying voltage. It can be regarded as a wire when it is turned on, and it is regarded as an open circuit when it is turned off. IGBT combines the advantages of BJT and MOSFET, such as low driving power and saturation voltage drop.

The IGBT module is a modular semiconductor product that is packaged by IGBT and FWD (freewheeling diode chip) through a specific circuit bridge. It has the characteristics of energy saving, convenient installation and maintenance, and stable heat dissipation.

IGBT is the core device of energy conversion and transmission, and the "CPU" of power electronic devices. The use of IGBT for power conversion can improve the efficiency and quality of electricity consumption, and has the characteristics of high efficiency, energy saving and green environmental protection. It is a key supporting technology to solve the problem of energy shortage and reduce carbon emissions.

IGBT is a composite device of Darlington structure with GTR as the leading component and MOSFET as the driving component. There are three electrodes outside it, namely G-gate, C-collector, E-emitter

During the use of the IGBT, the on/off/blocking state of the IGBT can be controlled by controlling the collector-emitter voltage UCE and the gate-emitter voltage UGE.

1) When the IGBT gate-emitter is applied with 0 or negative voltage, the internal channel of the MOSFET disappears, and the IGBT is turned off.

2) When the collector-emitter voltage UCE<0, the PN junction of J3 is in reverse bias, and the IGBT is in a reverse blocking state.

3) When the collector-emitter voltage UCE>0, there are two cases:

② If the gate-emitter voltage UGE<Uth, the channel cannot be formed, and the IGBT is in a forward blocking state.

② If the gate-emitter voltage UGE>Uth, the gate channel is formed, and the IGBT is in the on state (normal operation). At this time, holes are injected from the P+ region to the N base region for conductance modulation, reducing the value of the resistance RN of the N base region, and reducing the IGBT on-state voltage drop

Structurally speaking, IGBT mainly has three development directions:

1) IGBT vertical structure: non-transparent collector NPT type, PT type with buffer layer, transparent collector NPT type and FS electric field cut-off type;

2) IGBT gate structure: planar gate structure, Trench structure;

3) Silicon wafer processing technology: epitaxial growth technology, zone melting silicon single crystal;

Its development trend is: ① reduce loss ② reduce production cost

Total power dissipation = on-state loss (related to saturation voltage VCEsat) + switching loss (Eoff Eon). In the same generation of technology, the on-state loss and the switching loss are contradictory and mutually dependent.

According to the packaging process, IGBT modules can be mainly divided into two types: soldering type and crimping type. High-voltage IGBT modules are generally packaged in standard welded packages, while medium and low-voltage IGBT modules have many new technologies, such as sintering instead of welding, pressure contact instead of wire bonding crimping packaging process.

With the continuous development of IGBT chip technology, the maximum operating junction temperature and power density of the chip continue to increase, and the IGBT module technology must also adapt to it. In the future, IGBT module technology will be improved around the two aspects of soldering and fixing on the back of the chip and interconnection of front electrodes. Development trend of module technology:

No welding, no wire bonding and no liner/substrate packaging technology; internally integrate functional components such as temperature sensors, current sensors and drive circuits, and continuously improve the power density, integration and intelligence of IGBT modules.

The main application fields of IGBT：

As the mainstream device of new power semiconductor devices, IGBT has been widely used in traditional industries such as industry, 4C (communication, computer, consumer electronics, automotive electronics), aerospace, national defense and military industry, as well as rail transit, new energy, smart grid, new Strategic emerging industries such as energy vehicles

1) New energy vehicles：

IGBT modules play a vital role in electric vehicles and are the core technical components of equipment such as electric vehicles and charging piles. IGBT modules account for nearly 10% of the cost of electric vehicles and about 20% of the cost of charging piles. IGBT is mainly used in the following aspects in the field of electric vehicles:

A) Electric control system High-power DC/AC (DC/AC) drives the motor after inverter;

B) Vehicle-mounted air-conditioning control system Low-power DC/AC (DC/AC) inverter, using IGBT and FRD with low current;

C) Charging pile The IGBT module in the smart charging pile is used as a switching element;

2) Smart Grid：

IGBT is widely used in the power generation end, transmission end, substation end and power consumption end of the smart grid:

From the perspective of power generation, both rectifiers and inverters in wind power generation and photovoltaic power generation need to use IGBT modules. From the perspective of power transmission, the FACTS flexible power transmission technology in UHV DC transmission requires a large number of power devices such as IGBTs. From the point of view of the substation, the IGBT is the key device of the power electronic transformer (PET). From the perspective of power consumption, household white appliances, microwave ovens, LED lighting drivers, etc. all have a large demand for IGBTs.

3) Rail Transit：

IGBT devices have become mainstream power electronic devices for rail vehicle traction converters and various auxiliary converters. AC drive technology is one of the core technologies of modern rail transit. In the AC drive system, the traction converter is a key component, and the IGBT is one of the core components of the traction converter.

In a nutshell, power electronic components are needed in all places where electrical energy conversion is required. Including and not limited to IGBTs.