Novel test structures for extracting interface state density of advanced CMOSFETs using optical charge pumping

In this paper, we proposed novel test structures to evaluate the distribution of interface state density of MOSFETs by using optical charge pumping method. Unlike other measurement methods to extract interface state density (Dit), which have a limited range of measurable energy states and influenced by gate area and gate leakage, Dit can be extracted without these problems by using the proposed test structures. Test structures were fabricated using a 0.18μ CMOS process or FD-SOI technology with high-k dielectric, respectively. Optical charge pumping was performed in proposed test structures and Dit is extracted from 10⁹ cm⁻²· eV⁻¹ to 10¹³ cm⁻²· eV⁻¹.