Meet InSe: New high

Due to this, scientists, engineers, and microelectronics manufacturers have taken a keen interest in two-dimensional (2D) semiconductors, which are incredibly thin and almost devoid of height.

According to the engineers, thinner chip components would provide greater control and precision over the flow of electricity in a device while lowering the amount of energy required to power it. 

As such, a 2D semiconductor would also contribute to minimizing the chip’s surface area by forming a thin film over a supporting silicon device.  

In the past, scientists have experimented with designing 2D semiconductors that have performed well independently. However, their residue at excessively high temperatures damaged the underlying silicon chip.

While other semiconductors’s electronic features were lacking, including energy usage, speed, and precision, in other cases, those that met the temperature criteria could not attain the necessary purity level at the standard sizes expected in the industry.

Now, engineers have confronted these obstacles and achieved a breakthrough by creating a semiconductor material that can be deposited at sufficiently low temperatures to incorporate with a silicon chip seamlessly.

Seamless integration with silicon chips

The study was led by Deep Jariwala, Associate Professor, and Peter and Susanne Armstrong, Distinguished Scholar in the Department of Electrical and Systems Engineering (ESE), and Seunguk Song, the postdoctoral fellow.

Jariwal stated: “Semiconductor manufacturing is an industrial-scale manufacturing process. You aren’t going to have a viable material unless you can produce it on industrial-scale wafers.” 

“The more chips you can make in a batch, the lower the price. But the material must also be pure to ensure performance. This is why silicon is so prevalent — you can make it in large quantities without sacrificing purity.”

The new material – InSe, shows promise in revolutionizing computing chips, owing to its distinguished electrical charge-carrying capabilities.

However, producing the new material in large quantities has proven difficult due to its molecular proportions forming the medium. The study noted that it takes on chemical structures with varying ratios of each element, thus compromising its purity. 

The statement highlighted that the accomplishment relied on Song’s utilization of a growth technique that effectively managed the peculiarities of InSe's atomic structure.

Song said: “For the purposes of advanced computing technology, the chemical structure of 2D InSe needs to be exactly 50:50 between the two elements. The resulting material needs a uniform chemical structure over a large area to work.”

MOCVD growth technique led to breakthrough

Additionally, scientists revealed that the material's structure was achieved using a growth technique called – vertical metal-organic chemical vapor dispositions (MOCVD). 

Despite past research introducing the combination of Indium and selenium in equal proportions, the innovation was achieved by sourcing undesirable chemical structures in the material. 

As a result, the statement reported that the material produced molecules with varying ratios of each element. Contrarily, MOCVD operates by continuously delivering Indium and simultaneously introducing selenium in periodic pulses.

Sond explained that pulsing helps combine the Indium and selenium. “In the moments between pulses, you deprive the environment of selenium, which prevents the ratio from getting too high. The benefit of the pulse is the pause. That’s how we get a uniform 50:50 ratio across our entire full-size wafer.”

The engineers further illustrated control and alignment in the materials’ direction of crystals, enhancing the quality of their semiconductor even more by providing a seamless environment for electron transport.

“The two most important material qualities in semiconductors are chemical purity and crystalline order. The most important industrial quality is scalability. This material checks every box,” said Jariwala.

The study was published on August 9 in the journal – Matter.