Indium selenide, often referred to as a “golden semiconductor,” offers an ideal combination of properties.
Silicon just met its golden challenger.
In a landmark breakthrough, Chinese scientists have fabricated the world’s first wafer-scale, two-dimensional indium selenide (InSe) semiconductor, outperforming silicon and paving the way for next-gen chips.
Nicknamed the “golden semiconductor,” InSe has long tantalized researchers with its ideal mix of properties, including high electron mobility, suitable bandgap, and ultrathin profile.
But manufacturing it at scale proved elusive, until now.
A team or researchers led by Professor Liu Kaihui from Peking University, cracked the code using a novel “solid–liquid–solid” growth strategy that delivers unmatched crystal quality and phase purity across a full 2-inch wafer.
The study reports that InSe-based transistors beat silicon on multiple counts, showing electron mobility up to 287 cm²/V·s and ultra-low subthreshold swings at room temperature.
At sub-10nm gate lengths, the devices exhibited minimal leakage, high on/off ratios, and efficient ballistic transport, surpassing even the 2037 IRDS benchmarks for energy-delay product.
Crystal growth breakthrough
Achieving wafer-scale growth of InSe was no small feat. The material is notoriously tricky to work with due to extreme vapor pressure differences between indium and selenium and the tendency to form multiple stable phases.
These issues have long plagued attempts at large-area synthesis, often yielding only microscopic flakes.
To overcome this, the researchers developed a “solid–liquid–solid” conversion method. They began by sputtering an amorphous InSe thin film onto sapphire substrates.
The wafer was then capped with low-melting-point indium and sealed in a quartz cavity. Heating it to around 550 °C triggered a carefully controlled reaction, allowing indium to create a localized, indium-rich environment that drove uniform crystallization at the interface.
This resulted in a 2-inch InSe wafer with exceptional thickness uniformity, phase purity, and crystal structure, in an industry first.
Using these wafers, the team built high-performance transistor arrays that didn’t just work, they excelled.
Devices demonstrated electron mobility far beyond current 2D semiconductors, along with near-Boltzmann-limit switching behavior.
The transistors also showed strong performance at deeply scaled nodes, with reduced drain-induced barrier lowering (DIBL) and energy-delay products better than International Roadmap for Devices and Systems (IRDS) targets for 2037.
“This work represents an advancement in crystal growth,” reviewers of Science noted, underlining the global significance of the achievement.
Maintaining a perfect 1:1 atomic ratio of indium and selenium during growth has been a major bottleneck in 2D InSe synthesis. The team’s method effectively solves this, paving the way not just for InSe but potentially for a broader class of 2D semiconductors, including other chalcogenides with unstable phases.
What makes the breakthrough even more significant is its compatibility with existing CMOS processes, which could accelerate real-world integration. The researchers are now exploring heterointegration with other 2D materials to build multifunctional, vertically stacked chips.
Future applications include ultra-low-power AI accelerators, edge computing processors, and transparent or flexible electronics for smart devices.
With performance metrics that already exceed long-term silicon projections, wafer-scale InSe may soon become the backbone of the post-silicon era.
The study has been published in the journal Science.
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