MIT researchers have come up with a new way to build 3D chips that might change how smartphones and other electronics perform. The new method allows tiny GaN (gallium nitride) transistors to be added directly to regular silicon chips—something that was either too expensive or too complex before. This article will discuss everything about the latest 3D chip integration method, including its expected impact, key details, and potential applications.
3D GaN-on-Silicon Tech Overview
What’s Actually New Here
Instead of using full GaN wafers, which are costly, the team used small GaN “dielets”—each around 240 by 410 microns in size. These are laser-cut and then placed directly on top of silicon chips. This is done using copper connections instead of gold. That’s a big deal because copper is cheaper, easier to work with, and more conductive.
How It’s Bonded
The transistors are bonded using copper-to-copper contact at temperatures below 400°C. This bonding method doesn’t just cut costs—it also works with today’s standard semiconductor factories. So the process could actually be adopted without needing new equipment.
What They Built
The team tested this with a power amplifier built on Intel’s 22nm FinFET silicon. The result? It gave better signal strength, more bandwidth, and used less power than current chips made only with silicon. That’s promising if it ends up in actual phones.
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The Precision Part
Placing something this small on a chip isn’t easy. So, MIT designed a special tool that uses vacuum and precise microscopy to line up each transistor before bonding. Indeed, the level of alignment here is down to nanometers.
Availability and What’s Next
The research was officially presented at the IEEE RFIC Symposium in June 2025, under the title “3D‑Millimeter Wave Integrated Circuit (3D‑mmWIC)…”
Right now, it’s still in the research phase. But since it’s compatible with existing manufacturing systems, the transition to mass production might not be as far off as it seems. If it does go commercial, it could lead to much faster smartphones with longer battery life and better on-device AI.
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