Metrology solutions using optical scatterometry for advanced CMOS: III-V and Germanium multi-gate field-effect transistors

In this work, we report metrology solutions using scatterometry Optical Critical Dimension (OCD) characterization on two advanced CMOS devices: novel n-channel gate-last In 0.53 Ga 0.47 As FinFET with self-aligned Molybdenum (Mo) contacts and p-channel Ge FinFET formed on Germanium-on-Insulator (GOI) substrate. Key critical process steps during the fabrication of these advanced transistors were identified for process monitor using scatterometry OCD measurement to improve final yield. Excellent correlation with reference metrology and high measurement precision were achieved by using OCD characterization, confirming scatterometry OCD as a promising metrology technique for next generation device applications. In addition, we also further explore OCD characterization using normal incidence spectroscopic reflectometry (SR), oblique incidence spectroscopic ellipsometry (SE), and combined SR+SE technologies. The combined SR+SE approach was found to provide better precision.