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The layout and development of ROHM on semiconductor material Sic

Release on : Aug 12, 2019

Silicon carbide (SiC) has a 1X1 covalent bond of silicon and carbon compounds with a Mohs hardness of 13, second only to diamond (15) and boron carbide (14). As a semiconductor material, SiC has excellent properties, especially Power components for power conversion and control. At the same time, SiC also has low on-resistance, high-speed switching and high temperature and high pressure resistance.

In the production process, a specialized SiC substrate was developed and then processed in a fab to obtain a SiC-based power semiconductor. Many SiC-based power semiconductors and competing technologies are dedicated transistors that can switch the current of the device at high voltages. They are used in the field of power electronics to enable the conversion and control of power in the system.

The high voltage resistance of SiC products allows the device to use a thinner semiconductor layer (about 1/10) compared to Si material properties, and its conduction loss is very low.

Taking the two power devices of diode (PN, SBD) and transistor (IGBT, MOSFET) as an example, the advantages of SiC in this power device are as follows. In the diode, the Si-FRD structure voltage can reach 250V, and the SiC voltage can reach 4000V; the Si-MOSFET in the transistor can achieve 900V, and the market also has 1500V, but the characteristics will be worse, and SiC The product voltage can reach 3300V. At present, in the minority and multi-sub-devices with voltages exceeding 600V, SiC has an absolute advantage in on-resistance and switching speed. SiC materials have lower on-resistance, higher operating frequency and higher temperature resistance.

The use of SiC results in lower impedance, so it can have smaller size and higher efficiency; higher operating frequency can make passive components smaller; can operate at higher temperatures, making the cooling system simpler. Taking the 5kW LLC DC/DC converter commonly used in photovoltaic and automotive power systems as an example, the SiC chip area is only about 1/4 of that of Si-IGBT, and its weight is only about 1/8, and the loss can be reduced by 63%.

SiC can be used in many fields, and photovoltaics, including inverters, photovoltaic inverters, server power supplies, UBS, etc., have been used more frequently. These products have high conversion efficiency requirements. In recent years, with the development of new energy vehicles, SiC has many applications in pure electric vehicles and hybrid vehicles. SiC devices can improve the power conversion performance of pure electric vehicles or hybrid vehicles. SiC power devices can effectively improve their drive systems. For higher speed and efficiency. With the development of the market, SiC has also been widely used in energy, basic equipment, automotive, industrial and other equipment fields.

ROHM, one of the first manufacturers to mass produce SiC power components, began researching SiC in 2000. Until the acquisition of SiC wafers from SiC wafers in Europe in 2009, there was real progress. The SiC power module was introduced in 2010, and the trench type SiC MOSFET was first introduced in 2015. From 2000 to 2017, in the past 20 years, ROHM's SiC wafers have also evolved from 2 inches to 6-inch products (SiC-SBD). It can be said that ROHM's technology and products have been leading the development of the entire SiC industry.

In order to cope with the continuous expansion of the SiC market, ROHM has already made plans to increase SiC capacity two years ago. It is planned to increase SiC capacity to about 16 times in 2017 by 2025. This should be a bold investment. In addition, the gate driver for SiC will increase the capacity, because this is a complete solution.

ROHM's SiC discrete device lineup is divided into two major products: Schottky diodes, MOSFETs. Schottky diodes are divided into second and third generations, the second generation is a total of 650V, from 6A to 40a, 1200V, 5a to 40A; the third generation of JBS Schottky diodes, Roma first developed 650V products, From 2A to 20A, the next 1200V product will be developed; the MOSFET is divided into a planar second generation, trench type third generation.

ROHM is also the first manufacturer in the world to make full SiC power modules. ROHM has three package types, C type, E type, and G type. The difference is the size of the package. The larger the chip, the more chips can be placed. Can do bigger. ROHM's current products are mainly concentrated at 1200V, with a small current of 80A and a large current of 600A. ROHM has the strength to make chips, not only discrete devices, but also SiC wafers for some module factories. The products of the wafers are basically the same as the discrete devices provided by Roma. There are more MOSFETs, and the 650V is mainly concentrated in the third generation.

ROHM's development strategy focuses on automotive electronics and industrial equipment. The key products are mainly related to power supply, such as motor-driven IPM, analog IC, etc., as well as some standard products, and also focus on developing overseas markets. The world's largest supplier of new energy vehicles. ROHM has many automotive customers in China, including OEMs, Tier manufacturers, etc. Many automakers have already used ROHM SiC devices.

In new energy vehicles, ROHM SiC products are used in three places, one is the car charger, also called OBC, the other is the buck converter or the DCDC of the car, and the other is the car host inverter is also called electronic control. .

At present, the main drive is mainly IGBT, SiC application is under development, and it is expected to go to market after 2021. The first is the increase in mileage. The most effective way is to increase the capacity of the battery pack. The second is to shorten the charging time. The most direct and effective method is to increase the power of the charging pile or increase the power of the OBC. The third is higher battery voltage. For example, the traditional domestic electric vehicle is probably in the 400V system. In Europe, the 800V battery platform volume is introduced. A high voltage is promoted, the weight of the charging cable and the internal wire are reduced, and the weight of the car is finally reduced. The battery capacity can run even further.

In addition to SiC, the isolated gate driver (Gate Driver) is also a large market. In 2016, ROHM began mass production of single-chip integrated temperature monitoring, power supply magnetic isolation gate driver, currently in-vehicle magnetic isolation gate The driver IC market accounts for more than 80% of the market, ranking first in the world. It is estimated that by 2021, the production capacity of ROHM will increase by five times, and by 2025 it is expected to increase by 15 times.

In terms of general-purpose components, ROHM is centered on the growing automotive market and has established and strengthened its unshakable market position globally with its supply capabilities and reliability.

In order to become the world's top manufacturer, ROHM is continuously strengthening production and increasing production capacity. From 2017 to 2021, ROHM has a phased investment in SiC and plans to invest 85 billion yen by 2025. Capacity will increase sixfold by 2021 and will reach 16 times by 2025. ROHM also built a new Apollo plant covering an area of ​​20,000 square meters in Japan, mainly supplying wafers for SiC devices. Construction began in April 2019 and is expected to be put into use in 2021. Maintaining a long-term stable supply is the development policy that ROHM has always adhered to.