Improvement of existing limitation of AlGaInP material
Plan to demonstrate with Blue light
Expected to end the monopoly of global companies

Soft-EPi (CEO Sung-min Hwang), Gallium nitride specialized company, announced on the 2ndthat they have successfully developed a red gallium nitride EPi wafer that can improve micro light-emitting diode (LED) for the first time in Korea, and launching them.

Micro LED is referring to super small LED that is within 5~100㎛size. The difficulty of technology is very high but since it emits by itself, it does not need backlight. Since it has excellent brightness, contrast ratio, color reproduction, durability, and power efficiency, it is considered as a next-generation display.

Display technology using micro LED is considered a key technology for implementing the metaverse. It is necessary for next-generation displays such as augmented reality (AR), virtual reality (VR), and smart watches. micro LED implements a red LED using Aluminium gallium indium phosphide(AlGaInP) material. However, there are several difficulties due to the limitations of the physical properties.

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<InGaN RED LED, one Soft-EPi launched, emitting>
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<Wavelength spectrum of InGaN RED LED, one Soft-EPi launched.>

AlGaInP has a disadvantage that the smaller it gets, the efficiency of the chip drops dramatically due to the high surface recombination rate. Resolving this issue will result in poor LED temperature characteristics. Also, they can be mechanically weak, so the yield during the transfer process drops dramatically. The price of wafer is high, which increases the process cost.

EPi wafer with red gallium nitridehas received high interest in the related industry as an alternative to solve this problem. It is ideal to make red color with gallium nitride, which has same component as blue and red micro LED. However, due to the technical difficulty, there are only 4-5 companies globally who can produce red light with gallium nitride. However, it is impossible for micro LED developers to get red gallium nitride EPi, because the manufacturers have exclusive contract with META, Google, and others, and they are having difficult time to research and development (R&D).

Soft-EPi drew attention from industry when they developed and demonstrated red gallium nitride last year. Until recently, they have been focusing on performance improvement, and they have decided to launch EPi wafer with red gallium nitride. They plan to supply it to micro LED developers who want to purchase them.

EPi wafer with red gallium nitride can ultimately make red, green, and blue (RGB) on one wafer at a time, and build a foundation that can skip the transfer process or wafer bonding process. Soft-EPi has successfully integrated red and green into one wafer, and plans to integrate and demonstrate blue within this year.

In-sung Cho, head of Soft-EPi research center, said, "We still need to increase efficiency, but it is not insufficient compared to global companies. We will continue to work with customers to improve performance."

By Staff Reporter Han-sik Kim(