Experimental investigation of size effect on thermal conductivity for ultra-thin amorphous poly(methyl methacrylate) (PMMA) films

摘要

An investigation was conducted to determine whether a ?size effect?phenomenon for one particular thermophysical property, thermal conductivity, actuallyexists for amorphous poly(methyl methacrylate) (PMMA) films with thicknesses rangingfrom 40 nm to 2 ?m. This was done by using a non-contact, non-invasive, in-situTransient Thermo-Reflectance (TTR) laser based technique. The results demonstratedthat the intrinsic thermal conductivity of a 40 nm PMMA film deposited on native oxideof silicon increases by a factor of three over bulk PMMA values, and a distinct increasein the thermal conductivity of PMMA film was observed in ultra-thin (sub 100 nm)films. This confirmed the importance of film thickness for the through-plane thermalconductivity value of PMMA film on native oxide of silicon.