Researchers at MIT, along with collaborators from other institutions, have developed a new fabrication method that integrates high-performance gallium nitride (GaN) transistors onto standard silicon CMOS chips. This breakthrough addresses longstanding challenges related to the high cost and specialized integration requirements of GaN, significantly improving accessibility for a broad range of electronic applications.

Gallium nitride is the second most widely used semiconductor after silicon. Its unique electrical properties make it ideal for applications such as lighting, radar systems, and power electronics. However, to fully harness its capabilities, GaN-based chips must be connected to silicon-based digital chips, commonly known as CMOS chips.

The team’s approach involves fabricating numerous miniature GaN transistors on a GaN wafer. Each of these transistor units, or “dielets,” measures just 240 by 410 microns. These dielets are then separated and bonded onto a silicon chip using a low-temperature copper-to-copper bonding process. This technique preserves the integrity and performance of both materials.

By integrating only a small amount of GaN with silicon, the researchers keep manufacturing costs low while significantly enhancing chip performance. The placement of discrete GaN transistors across the silicon surface also helps reduce heat, improving thermal management.

To demonstrate the effectiveness of their method, the team built a power amplifier—a critical component in mobile phones. This amplifier outperformed those using traditional silicon transistors, delivering stronger signals and greater energy efficiency. Potential benefits include clearer calls, faster wireless speeds, better connectivity, and longer battery life in mobile devices.

MIT graduate student Pradyot Yadav, the study’s lead author, emphasized the practical value of the innovation. He pointed out that the combination of lower cost, better scalability, and superior performance makes this hybrid technology an obvious choice for future adoption. The integration of the best features of silicon and GaN could open the door to transformative advances across multiple commercial sectors.

The new process is also compatible with existing semiconductor manufacturing infrastructure. It employs standard fabrication techniques and avoids expensive materials like gold and high-temperature processing that could damage conventional equipment. This compatibility ensures the new method can be readily adopted to improve both current electronics and next-generation technologies.

Looking ahead, the researchers believe this integration could extend beyond consumer electronics to support quantum applications. GaN performs well at the cryogenic temperatures needed for certain types of quantum computing, suggesting potential for broader impacts in advanced computing fields.

By Impact Lab