News: Microelectronics
15 December 2023
CEA-Leti develops CMOS-compatible 200mm GaN-on-silicon process close to state-of-the-art GaN/SiC performance
Micro/nanotechnology R&D center CEA-Leti of Grenoble, France has developed a 200mm gallium nitride/silicon (GaN/Si) process technology compatible with CMOS cleanrooms that preserves the high performance of the semiconductor material but costs less than existing GaN/SiC technology.
In one of nine presentations at the 69th annual IEEE International Electron Devices Meeting (IEDM 2023) in San Francisco (9–13 December), the institute noted that existing GaN high-electron-mobility transistor (HEMT) technologies used in telecom or radar applications come on small GaN/SiC substrates and require processing in dedicated cleanrooms.
The high-performance SiC substrates used to grow GaN layers are very expensive and available only in relatively small size. The CEA-Leti R&D project developed GaN/silicon technology (GaN/Si) on 200mm and later for 300mm wafer diameters in CMOS-compatible cleanrooms to reduce substrate cost and to benefit from existing high-performance cleanroom facilities.
As a result, CEA-Leti’s GaN/Si technology performance at 28GHz is gaining ground on GaN/SiC technology in terms of power density.
“Our goal was to reach existing state-of-the-art GaN HEMT performance at ~30GHz with a 200mm CMOS- compatible GaN/Si technology and to compete with GaN/SiC technology,” said Erwan Morvan, CEA-Leti scientist and lead author of the paper ‘6.6W/mm 200mm CMOS Compatible AlN/GaN/Si MIS-HEMT with In-Situ SiN Gate Dielectric and Low Temperature Ohmic Contacts’.
Picture: Scanning transmission electron microscopy cross section of the AlN/GaN MIS-HEMT and zoom on the gate foot.
“This work demonstrates that CMOS-compatible 200mm SiN/AlN/GaN MIS-HEMT on silicon technology is a promising candidate for applications like 5G/6G infrastructure, satcom, radar for UAV detection or earth observation,” he added. “It should enable less expensive devices while keeping high power density, high efficiency, light weight and compactness.”
The devices developed in this work, which are designed for RF amplifiers and switches, can be used in those applications around 30GHz.
While reliability testing on the process technology is just beginning, CEA-Leti’s ongoing R&D in this area will include increasing the raw output power and efficiency of its MIS-HEMT transistors, integrating its improved process modules to boost device performance and increase operation frequency toward 100+GHz, and 3D integration of GaN/Si chips on 300mm silicon wafers.
