OKI and NTT Innovative Devices Develop Mass Production Technology for High-Power Terahertz Devices

OKI, in collaboration with NTT Innovative Devices Corporation, has developed mass production technology for high-power terahertz devices using crystal film bonding (CFB) technology. This process bonds indium phosphide (InP)-based uni-traveling carrier photodiodes (UTC-PD) onto silicon carbide (SiC) substrates to enhance heat dissipation and improve bonding yields. The technology targets applications in 6G communications and non-destructive sensing, with mass production planned for FY2026.
Terahertz waves, located between radio waves and visible light, offer penetration and straight-line propagation properties, making them suitable for non-destructive inspection and security applications due to their non-invasiveness compared to X-rays. In wireless communications, higher carrier frequencies increase communication capacity, but terahertz waves face significant atmospheric attenuation, necessitating high-power devices.
NTT Innovative Devices enhanced UTC-photomixer performance, focusing on output power and spectrum. By bonding InP-based UTC-PDs to SiC, the collaboration achieved an output power at 1dB compression exceeding 1 mW, a ten-fold improvement over conventional devices. OKI’s CFB technology divides InP-based crystal films at the device level, selectively bonding them to SiC wafers, increasing bonding yields from approximately 50% to nearly 100% and improving...