For more than half a century, Moore’s Law has been the guiding principle of electronicsprompting the industry to reduce the size of transistors to double the power of microchips every two years. However, this path towards the infinitesimally small today collides with an insurmountable barrier: the quantum limit.
What does this mean? That When the distance between transistors (the famous nanometers of a microchip) approaches the size of just a few atoms, the laws of classical physics no longer apply. and begin to master the strange rules of quantum mechanics. In this tiny world, electrons can “tunnel” through the barriers that should contain them, causing transistors to lose their ability to reliably turn on and off. It is the final physical wall of miniaturization.
Faced with this challenge, a team from the King Abdullah University of Science and Technology (KAUST) in Saudi Arabia has not only confirmed that the end of one era is near, but has pointed the way to the next. They have created the first hybrid integrated circuit with six stacked layersan unprecedented advance that marks a new direction: when the space on the microchip can no longer be reduced, the only way out is to grow vertically. The advance has been published in Nature.
“Historically, the semiconductor industry has focused on reducing the size of transistors to increase integration density. But We are reaching a limit of quantum mechanics and the cost is skyrocketing – explains Xiaohang Li, leader of the study, in a statement -. To continue moving forward, we must look beyond planar scaling; “stacking transistors vertically is a promising solution.”
Until now, no one had managed to overcome two layers in hybrid chips. The KAUST team has not only done it, but has quadrupled the record, reaching six functional layers.
Achieving this feat was not easy. Stacking microchip layers is often a brutal process that requires hundreds of degrees of temperature, damaging the lower layers as the upper ones are added. The KAUST team devised a process based on three steps. The first was to perfect the texture of each layer, making it smoother than in previous processes. The second was to achieve perfect alignment, thereby guaranteeing that each floor of the “skyscraper” connected optimally with the next.
And finally, chase a low temperature. No manufacturing step exceeded 150°C, and most were performed at near room temperature, preserving the integrity of the entire assembly.
This method is not only an achievement in itself, but, as Saravanan Yuvaraja, co-author of the study, states, “provides a plan to scale up and increase functional density far beyond current limits.”
This breakthrough paves the way for a new generation of more powerful, smaller and more efficient devices, crucial for flexible electronics, smart health and the Internet of Things. It is not the end of progress, but the beginning of a new dimension: the vertical.