Schematic diagram of an indium-gallium-arsenide (InGaAs) photodiode image sensor integrated on a guided mode resonance structure (left) and a photograph of the fabricated wafer and scanning microscopy image of the periodic lattice structure (right).[KAIST 제공]
[헤럴드경제=구본혁 기자] A joint research team in Korea and the United States has developed a next-generation high-resolution image sensor technology that is more power efficient and smaller than existing sensors. It is assessed that there is a high possibility of entering the market in the future by securing the original technology for ultra-high-resolution shortwave infrared (SWIR) image sensor technology, which Sony is leading in the global market.
KAIST announced on the 1st that the ultra-thin broadband photodiode (PD) developed by Professor Sang-Hyun Kim’s (photo) team in the Department of Electrical and Electronic Engineering through joint research with Inha University and Yale University in the United States has created a new turning point in high-performance image sensor technology.
This research has dramatically improved the trade-off between absorption layer thickness and quantum efficiency that appears in existing photodiode technologies. In particular, high quantum efficiency of more than 70% has been achieved even in an absorption layer as thin as 1 micrometer (μm) or less. This achievement resulted in a reduction of the thickness of the absorption layer of existing technology by approximately 70%.
As the absorption layer becomes thinner, the pixel process becomes simpler, making it possible to achieve high resolution, and carrier diffusion becomes smooth, which is advantageous in obtaining optical carriers. In addition, costs can be reduced. However, there is an inherent problem that in general, as the absorption layer becomes thinner, the absorption of long-wavelength light decreases.
By introducing a guided mode resonance (GMR) structure, the researchers demonstrated that high-efficiency light absorption can be maintained over a wide spectral range from 400 nanometers (nm) to 1,700 nanometers (nm). This wavelength band is expected to play an important role in a variety of industrial applications, including not only the visible light region but also the shortwave infrared (SWIR) region.
Sang-Hyun Kim is a professor in the Department of Electrical and Electronic Engineering at KAIST.[KAIST 제공]
Performance improvements in the shortwave infrared region are expected to make a significant contribution to the development of next-generation image sensors with increasingly higher resolution. In particular, the waveguide mode resonance structure has the potential to further increase resolution and other performance through hybrid integration with complementary metal oxide semiconductor (CMOS)-based signal read-out circuit (ROIC) and monolithic 3D integration.
By increasing the international competitiveness of low-power devices and ultra-high-resolution imaging technology, the research team has greatly increased the feasibility of realizing future ultra-high-resolution image sensors in areas ranging from digital cameras, security systems, medical and industrial image sensor applications to autonomous automobile driving, aviation and satellite observation.
Professor Sanghyun Kim said, “Through this research, we have proven that even ultra-thin absorbers can achieve much higher performance than existing technologies,” adding, “In particular, the original technology for ultra-high-resolution shortwave infrared (SWIR) image sensor technology, which Sony is leading in the global market. “We have opened up the possibility of entering the market in the future,” he explained.
The results of this research were published in the international academic journal ‘Light, Science and Applications’.
Section 4: The Role of Hybrid Structures in Ultra-High-Resolution Image Sensors
Question 1: What is the significance of this joint research team’s development of a next-generation high-resolution image sensor technology, and how does it differ from existing sensors in terms of power efficiency and size reduction?
Question 2: Could you explain the challenges involved in achieving high-efficiency light absorption in ultra-thin absorption layers, and how the introduction of guided mode resonance (GMR) structure addresses these challenges?
Question 3: How does the improved performance in the shortwave infrared region contribute to the development of next-generation image sensors with increasing resolution?
Question 4: In what ways does the use of a guided mode resonance structure hybridized with complementary metal oxide semiconductor (CMOS)-based signal read-out circuit (ROIC) and monolithic 3D integration enhance the feasibility of realizing future ultra-high-resolution image sensors?
Question 5: How does this research potentially impact the market for image sensors in various industries such as digital cameras, security systems, medical imaging, and autonomous automobile driving?
Question 6: How does the development of this technology strengthen Korea’s position in the global market for image sensors, particularly in relation to Sony’s dominance in the ultra-high-resolution shortwave infrared (SWIR) image sensor technology sector?
Section 1: Introduction and Overview of the Research
This section introduces the joint research team’s development of a next-generation high-resolution image sensor technology that is more power efficient and smaller than existing sensors. It also covers the significance of this breakthrough and its potential impact on the market.
Section 2: Challenges and Solutions in Achieving High-Efficiency Light Absorption in Ultra-Thin Absorption Layers
The discussion in this section focuses on the challenges associated with achieving high-efficiency light absorption in ultra-thin absorption layers and how the introduction of the GMR structure addresses these challenges.
Section 3: Performance Improvements in the Shortwave Infrared Region
This section explores the role of the improved performance in the shortwave infrared region in the development of next-generation image sens
