Author: Bodo’s Power Systems Magazine Editorial Department

1, the strongest power semiconductor IGBT and domestic leader

IGBT is a composite fully controlled power semiconductor with low driving power and low saturable voltage. It is the CPU of power electronic devices. Since its inception, through continuous technological innovation, IGBT device structure and process technology have made great progress, and the product has gone through 7 generations of development. By adopting industrial technologies such as trench gate, field stop (FS), light punch-through (LPT), soft punch-through (SPT), carrier storage (CS) layer, floating P-type region, virtual gate, micro-trench gate (MPT), thin film processing, back H ion implantation, etc., the reliability, application frequency and power loss of the device have been greatly improved【1】.

According to data from the China Economic Industry Research Institute, as the global IGBT industry has developed positively in recent years, the market size has also increased year by year. In 2021, the global IGBT market size was approximately US$7.09 billion, a year-on-year increase of 6.6%. Data from TrendForce also showed that the Chinese market was US$3.96 billion, accounting for 59%, making it the world's largest IGBT market.

Looking at the IGBT field, it is almost monopolized by companies in the United States, Europe and Japan. The important reason is that the design and manufacturing of IGBT chips and the design, manufacturing and testing of IGBT modules require extremely high talent and equipment, and it is an industry that is difficult to overtake. However, my country has always faced the problem of "stuck neck" in this field. Although the barriers to IGBT are high, the only way out for domestic power semiconductors is independent innovation and seeking domestic substitution.

As a Chinese local enterprise, SUN.KING Technology focuses on self-developed IGBT technology. It currently produces the i20 chipset, which is superior to the 4th generation chips of other mainstream manufacturers in the world. And actual measurements show that compared with the same specification chips of peer companies, SUN.KING Technology's chip power is 250A, and the performance is improved by more than 10%.

2, SunKing Technology’s self-developed i20 IGBT core technology was born

2.1, i20 and d20 chipset introduction

The voltage/current of a single wafer of the i20 IGBT chip and d20 FRD chip that SUN.KING Technology has mass-produced is 1200V/250A, and the performance reaches or exceeds similar products of international leading companies. The i20 IGBT chip adopts a fine trench gate-field stop (Fine Pattern Trench- Field Stop) structure and is connected to the N-type enhancement layer (N- Enhancement layer), narrow mesa, short channel, ultra-thin base, optimized P+ LAYER, advanced 3D structure and other optimization designs further improve the IGBT on-saturable voltage drop and switching loss trade-off performance, while greatly increasing the current controllability (di/dt controllability) and short-circuit robustness.

In order to ensure that the overall performance of IGBT is further exerted, SUN.KING Technology has also optimized the design of the IGBT matching freewheeling diode chip d20. Through advanced emitter injection efficiency management (Advanced Emitter efficiency management), optimized anode diffusion profile (Anode: Diffusion profile optimization), cathode laser return process (Cathode: laser annealing) and other technologies to achieve a compromise balance between lower conduction voltage drop and reverse recovery loss, while through electron irradiation lifetime control technology (Electron irradiation lifetime control) and thin base thickness tuning (thin base thickness tuning) and other technologies to achieve d20 signal high di/dt reverse recovery characteristics and no oscillation, and optimize the d20 terminal design to further improve the dynamic robustness of the diode.

2.2, i20 and d20 switch characteristics test

In order to verify the superiority of the switching characteristics of the i20 and d20 chipsets, SUN.KING Technology conducted a comparative test on the mass-produced 1200V 750A ED series module SISD0750ED120i20 with the same platform module of the same IGBT4 of the international leading enterprise in the industry. It should be noted that the current maximum junction temperature of the IGBT4 module is only 150℃. Through comparison, it is found that the turn-on loss of the two modules is basically the same, and the turn-off loss of the ED module using the i20 chipset is slightly higher, but the ED module with saturable conduction voltage drop is lower. The diode of the ED module based on the d20 chipset has the same forward voltage drop as the IGBT4, and can maintain a lower reverse recovery loss. From the test, the modules using the i20 and d20 chipsets are better than the similar 4th generation IGBT modules of international leading enterprises.

2.3, safe workspace testing

IGBT 600;">Short Circuit Safe Operating Area (SCSOA)

The i20 chipset has excellent short-circuit robustness. Figure 4 below shows the short-circuit waveform of the ED module tested at 175℃ shell temperature and 800V bus voltage. The short-circuit current is only about 3 times the rated current, and the short-circuit waveform has no oscillation. The module short-circuit duration can reach 15us, which provides a guarantee for real-time and rapid protection of the circuit.

SC mode: > 15μs @ V<span style="box-sizing: border-box; margin: 0px; padding: 0px; list-style: none; border: 0px; outline: none; font-size: 12px; line-height: 0; position: relative; style=" box-sizing:="" border-box;="" margin:="" 0px;="" padding:="" list-style:="" none;="" border:="" outline:="" font-size:="" 12px;="" line-height:="" 0;="" position:="" relative;="" vertical-align:="" baseline;="" bottom:="" -0.25em;"="">CE= 800V

IGBTReverse Bias Safe Operating Area (RBSOA)

Another aspect related to IGBT reliability is the reverse bias safe operating area of the device. Generally, the RBSOA boundary given by the module manufacturer is twice the rated current. In order to test the RBOSA boundary of the i20 chip to determine the damage limit, SUN.KING Technology started the device from twice the rated current and gradually increased the current. The test found that the i20 chip can be safely turned off at about 3 times the nominal current. When the current is further increased, the device will reach saturable, at which time the device can still be turned off normally, greatly widening the RBSOA working area.

Increase the current IC=1500A (=2.5 times nominal) 2000A (>3 times), VDC=800V

Diode safe operating area (DSOA)

The diode's safe operating area mainly depends on the diode's switching characteristics. To evaluate the robustness of the diode, the commutation speed of the diode was increased by reducing the external gate resistor Rgon to its minimum value and then increasing the gate voltage Vge. Double pulse tests were performed for selected extreme cases: 750A current and 900V reverse voltage, with an IGBT turn-on voltage of 21V. The experiment found that at a case temperature of 175°C, the peak power of the diode exceeded 800kW, the di/dt exceeded 10kA/us, and the device remained stable. The selected test conditions far exceeded any data sheet recommendations, further demonstrating the high reliability of SUN.KING Technology's d20 chipset.

I=750A，VGE_on=21V

2.4、Inverter efficiency comparison simulation

In order to verify the performance of i20 and d20 chipsets at the system application level, the ED type 750A half-bridge module based on i20 chipset was compared with the competitor i4-600A and i7-750A modules in rectification mode and inverter mode respectively. The performance curve reflects the relationship between the inverter output power (or current) and the switching frequency. The simulated thermal resistance value is taken from the data sheet, and the static and dynamic losses of the device are taken from the measured values. Under inverter conditions, the ED-750A rated module consumes 3% less power than the most advanced i7 740A module in the worst case, reaching a balance when the switching frequency reaches 3kHz. Compared with the i4-600A module, which is currently the most widely used, the ED type module can improve performance by more than 10%. In rectifier mode, the performance of SUN.KING Technology's ED module is basically the same as the latest i7-750A module, and compared with the i4-600A module, the performance can also be improved by more than 10%.

Figure 7: Performance in rectifier and inverter modes 

3, domestically produced chips are favored by the market with excellent performance, and SUN.KING Technology has ushered in a period of accelerated sales

Through the above switching characteristic test, safe working area test and inverter efficiency comparison simulation, it is found that SUN.KING Technology's i20 chipset has obvious advantages and gradually stabilizes customers in market applications. SUN.KING Technology continues to invest heavily in the research and development and promotion of new products, and has achieved remarkable results.

In June 2021, SUN.KING Technology's first IGBT module production line with world-class level and intelligent full-automatic was completed and put into mass production. The ED packaged IGBT module series manufactured by this production line has been tested by several companies in the fields of electric vehicles, wind power, photovoltaics and industrial electronic control.

At the end of 2021, SUN.KING Technology's independently developed IGBT chips completed their first batch delivery (in the form of wafers) to customers in the new energy passenger vehicle market. This indicates that the IGBT chips using SUN.KING i20 technology have been recognized by mainstream new energy vehicle manufacturers in the market and have entered the mass sales stage.

In early 2022, SUN.KING Technology signed the first bulk purchase framework agreement involving tens of thousands of ED packaged IGBT modules with a well-known domestic photovoltaic company. A domestic breakthrough has been achieved in the field of centralized photovoltaic power generation, which is almost monopolized by foreign IGBT products. This is also the first batch order for SUN.KING Technology's self-developed technology IGBT modules, a milestone event for obtaining customer recognition and starting mass sales and applications.

In addition, the company's silicon carbide product layout is also being launched, and the first generation of silicon carbide modules is expected to be launched this year. It is reported that the chip and module technology developed by SUN.KING will cover the IGBT module market such as electric vehicles, new energy power generation, and industrial electric control. From this we can see that SUN.KING Technology is actively expanding its advantages in the field of IGBT chips, and is still moving forward, and is bound to complete the mission of localization. The dawn of domestic substitution is also becoming brighter step by step.

4, with the support of top R&D team, domestic IGBT stands out 

The IGBT field is technically difficult, and its technical barriers require the R&D team to have rich knowledge reserves and practical experience. SUN.KING Technology has always attached great importance to technology research and development and is committed to becoming an internationally leading technology research and development company. To this end, SUN.KING Technology has absorbed a large number of industry leaders and R&D personnel with excellent performance and decades of practical experience in the field of power semiconductors.

ABB Semiconductor is a leading company in the power electronics industry. Its IGBT and other power semiconductor devices are specifically used in locomotive traction, industry and energy transmission and other fields that require high reliability. Xiang Jie, chairman and founder of SUN.KING Technology, worked at ABB Semiconductor headquarters in Switzerland from 1999 to 2001. During this period, he not only went deep into every link of the first IGBT production line, but also participated in the design and development, project management, market analysis and other positions, and had a deep understanding of the entire process of IGBT R&D and production.

The IGBT expert team led by Chairman Xiang Jie is mainly composed of the original ABB semiconductor technology team. The team members have published many technical papers and have dozens of patents, and truly possess the world's top technical strength and experience.

For example, Mr. Roland Villiger has excellent executive management performance and more than 25 years of industry experience in the field of power semiconductor technology. Dr. Sven Matthias has published 25 IGBT-related academic papers and has 6 patents. He has extremely high technical attainments and rich experience in power semiconductor design and development and process manufacturing. Mr. Zhang Qiang, the person in charge of the domestic side, has published 3 IGBT-related papers, has 3 patents, and also has rich experience in IGBT process manufacturing.

There are countless outstanding talents like this in SUN.KING Technology. SUN.KING Technology is also good at combining excellent international technical teams with excellent domestic talents, and invests a lot of money every year to focus on research and development. With the advanced ideas and foresight of Chairman Xiang Jie, everyone worked together to create new breakthroughs one after another in SUN.KING Technology. It is precisely because of such an excellent and mature team that SUN.KING Technology has achieved market-competitive IGBT chips and module products.

Today, with more than a century of industry experience, the SUN.KING Technology R&D team is actively committed to inspiring and implementing sustainable solutions with business, striving to achieve sustainable development in the future.

5 600;">, ready to go, move forward

As electric vehicles move towards high power density, high safety and low cost, the current density, power loss and reliability of power devices play a key role. Cell and body structure optimization and intelligent integration technology are the fundamental ways to achieve the above goals. In the future, IGBT devices will move towards trench gate structure, refined graphics, carrier injection

enhanced modulation, and thin-film processing technology. SUN.KING Technology will also continue to improve itself with the development of IGBT chip technology, forge ahead and take off.

www.sunking-tech.com

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