A team of Korean researchers has developed innovative p-type semiconductor materials and thin-film transistors that could revolutionize the semiconductor and display industries.
This breakthrough, led by the Electronics and Telecommunications Research Institute (ETRI), is expected to greatly improve the performance of next-generation displays and low-power semiconductor devices.
The research, which focuses on a new Selenium-Tellurium (Se-Te) alloy, was recently published in the journal ACS Applied Materials & Interfaces.
Semiconductors are essential in modern electronics, powering everything from smartphones to televisions.
They come in two main types: intrinsic and extrinsic. Intrinsic semiconductors are “pure” materials with no added impurities, but these pure materials, like silicon, don’t allow electricity to flow easily.
To make them more useful, small amounts of other materials, or impurities, are added to create extrinsic semiconductors, which can conduct electricity.
Extrinsic semiconductors are further classified into two types: n-type and p-type. The n-type semiconductors are made by adding materials that provide extra electrons, while p-type semiconductors are created by adding materials that create “holes” for electrons to move through.
These p-type and n-type semiconductors are used together in devices like transistors, which control the flow of electricity in electronics.
While n-type semiconductors, like IGZO (Indium Gallium Zinc Oxide), are widely used in displays, p-type semiconductors have been more difficult to produce and use.
P-type Low-Temperature Polycrystalline Silicon (LTPS) is often used, but it is expensive to manufacture and can only be made in small sizes.
As the demand for higher-quality displays with faster refresh rates increases, especially with the rise of 8K resolution and beyond, the need for better p-type semiconductors has grown.
To meet this demand, researchers at ETRI have developed a new p-type semiconductor material by combining selenium (Se) and tellurium (Te). This Se-Te alloy offers several important advantages.
It can be deposited at room temperature using a simple process and then crystallized through heat treatment, allowing for the creation of thin, amorphous films.
These films have better mobility (how easily electrons can move through the material) and a higher on/off current ratio than previous p-type transistors, making them more efficient.
Additionally, the team found that introducing a Te-based p-type semiconductor into a heterojunction structure—where two different semiconductor materials are layered together—improves the performance of n-type transistors.
This is achieved by controlling the flow of electrons within the n-type transistor based on the thickness of the Te layer.
This method also improves the stability of n-type transistors without the need for an extra passivation layer, which is typically required to protect the transistor from environmental factors.
This discovery is expected to have a significant impact on the next generation of displays, including OLED TVs and extended reality (XR) devices.
The new Se-Te-based p-type semiconductors not only enhance the performance of displays by supporting faster refresh rates and higher resolutions, but they also reduce power consumption.
This is particularly important as the demand for energy-efficient devices continues to rise.
In addition to improving displays, this breakthrough could have far-reaching effects in other areas of technology.
The new semiconductors could be used in complementary metal-oxide-semiconductor (CMOS) circuits, which are essential for a wide range of electronic devices, as well as in DRAM memory, a type of memory used in computers and smartphones.
One of the biggest challenges in the semiconductor industry is finding ways to pack more power into smaller devices without increasing costs or complexity.
Current approaches, like Through-Silicon Vias (TSV), involve stacking multiple semiconductor wafers on top of each other and drilling holes to connect them. While this method is effective, it is expensive and difficult to produce at scale.
An alternative approach, called Monolithic 3D (M3D) integration, involves stacking layers of semiconductors on a single wafer. While this method could be more efficient, it hasn’t yet been commercialized because of the challenges involved in using high-temperature processes.
However, the new heterojunction transistors developed by ETRI can function at lower temperatures (below 300°C), which could help bring M3D integration closer to reality.
The researchers at ETRI plan to continue optimizing the Te-based p-type semiconductors for larger substrates, such as those over six inches in size, to make them more practical for commercial use.
They are also exploring ways to apply this technology to a variety of circuits, potentially opening the door to new applications in fields like flexible electronics and sustainable energy.
“This is a monumental achievement that can be widely utilized in next-gen displays and beyond,” said Cho Sung-Haeng, Principal Researcher of ETRI’s Flexible Electronics Research Section.
“We believe this technology will shape the future of semiconductors, displays, and many other areas of research.”
With these promising developments, the new p-type semiconductor materials could lead to more efficient, affordable, and environmentally friendly electronics, ushering in the next era of innovation in the semiconductor industry.
