High-resolution transmission electron microscopy of III-V FinFETs

Abstract

III-V materials have great potential for integration into future complementary metal-oxide-semiconductor technology due to their outstanding electron transport properties. InGaAs n-channel metal-oxide-semiconductor field-effect transistors have already demonstrated promising characteristics, and the antimonide material system is emerging as a candidate for p-channel devices. As transistor technology scales down to the sub-10-nm regime, only devices with a 3D configuration can deliver the necessary performance. III-V fin field-effect transistors (finFETs) have displayed impressive characteristics but have shown degradation in performance as the fin width is scaled to the sub-10-nm regime. In this work, we use high-resolution transmission electron microscopy (HRTEM) in an effort to understand how interfacial properties between the channel and high-k dielectric affect device performance. At the interface between the channel material, such as InGaSb or InGaAs, and the high-k gate dielectric, properties of interest include defect density, interdiffusion between the semiconductor and dielectric, and roughness of the dielectric - semiconductor interface. Using HRTEM, we can directly study this interface and try to understand how it is affected by different processing conditions and its correlation with device characteristics. In this thesis, we have analyzed both InGaAs and InGaSb finFETs with state-of-the-art fin widths. Analysis of TEM images was combined with electrical data to correlate interfacial properties with device performance. We compared the materials properties of InGaAs and InGaSb and also explored the impact of processing steps on interfacial properties.