Diamond-Like Carbon Thin Films with Extremely High Compressive Stress (>8~12GPa) for Advanced CMOS Strain Engineering
- PDF / 669,852 Bytes
- 6 Pages / 612 x 792 pts (letter) Page_size
- 43 Downloads / 135 Views
Diamond-Like Carbon Thin Films with Extremely High Compressive Stress (>8~12GPa) for Advanced CMOS Strain Engineering Xiaolong Ma1, Huaxiang Yin1, Zuozhen Fu1, Haiqiang Zhang2, Xu Zhang2, Jiang Yan1, Chao Zhao1, Dapeng Chen1, Tianchun Ye1 1 Key Laboratory of Microelectronics Devices and Integrated Technology, Institute of Microelectronics of Chinese Academy of Sciences, 100029, Beijing, China 2 Key Laboratory of Beam Technology and Material Modification of Ministry of Education, Beijing Normal University, 1000875, Beijing, China ABSTRACT Diamond-like carbon (DLC) films as a new strain-capping material with compressive stress up to 12GPa for strained silicon technology were fabricated by filtered cathodic vacuum arc (FCVA) deposition system. The films’ compositions and bonding structures were characterized using multi-wavelength Raman spectroscopy. The relationship between intrinsic stress and G peak dispersion of the films’ Raman spectra were discussed. The results showed that the bias voltage applied to substrate during deposition determines films’ sp3 bonding content and intrinsic stress. Process compatibility of the DLC films with standard CMOS technology was confirmed by using WDXRF measurement. Also diffusion behavior of carbon atoms in DLC films with copper and silicon was studied with a Cu(200nm)/DLC(40nm)/silicon multilayer structure annealed at 500℃ in N2 atmosphere for an hour. At last, stress induced on silicon surface by DLC strips was characterized using surface sensitive UV-Raman spectroscopy. The results showed that DLC films with extremely high compressive stress have potential application in future CMOS strain engineering. INTRODUCTION During the past decade, uniaxial strain engineering has been the dominant technique to successfully enhance silicon MOSFET performance since the embedded SiGe source/drain was firstly introduced into 90nm technology node. With different materials and process methods, a series of strain technologies have been explored to achieve further improvements in advanced CMOS technology [1]. However, as gate pitch was successively reduced, the stress induced in the channel by the traditionally silicon nitride capping layer starts to decline due to the reduced inter-gate space. DLC film normally demonstrated very high compressive stress and is more suitable as strain capping layer than conventional silicon nitride [2]. In this present study, DLC thin films with extremely high compressive stress were fabricated by using FCVA method. The DLC films’ characteristics, process compatibility and strain transfer mechanism were studied. THEORY AND EXPERIMENT Generally, carbon film includes a great variety of crystalline and disordered structures and contains three hybridizations configurations such as sp3, sp2 and sp1 [3]. In the sp3 configuration, a carbon atom’s four valence electrons are each assigned to a tetrahedrally directed sp3 orbital, which makes a strong sigma (σ) bond to an adjacent atom. DLC is a special carbon material that can have more than 80% sp3 bonds and some extreme p
Data Loading...
