Tensile Strength and Deviation Analysis of Micro-scaled Silicon Structure with Full-coated PECVD DLC Film

Abstract

The influence of deposition bias voltage on the tensile properties of single-crystal silicon microstructure fully coated with 150 nm-thick diamond like carbon film using plasma enhanced chemical vapor deposition were investigated. The fabricated structure had dimensions of 120 μm long, 4 μm wide and 5 μm thick. PECVD DLC film has the average sp² phase of 44%, sp³ phase of 20% and hydrogen content of 36% from photoelectron spectroscopy (XPS), and thermal desorption spectrometry (TDS) analysis. With increasing negative bias voltage, sp³ phase increased and sp² phase, hydrogen content decreased. The tensile strength of DLC coated SCS samples was 13.2%-29.6% higher compared to the bare silicon samples. The -400 V bias showed the highest strength of 3.94 GPa, which was in a good agreement with the measurement result of DLC fracture toughness. The deviation in strength reduced significantly with increasing negative bias voltage.