Thin-film Thermal Conductivity and Thickness Measurements Using Picosecond Ultrasonics
نویسنده
چکیده
A method utilizin g picosecond u ltrason ics, combin ed with a pump-probe therm oreflectance techn iqu e, for the sim u ltan eou s m easu rem ent of thin -film th ickness and thermal condu ctiv ity norm al to the su rface is presen ted. Th is techniqu e is a non con tact m ethod that is u sefu l for determ in in g thermophysica l properties of film s with th ickness grad ien ts or for film s in wh ich the th ickness is n ot a known parameter. The thermal conductiv ity of a th in tungsten film is extrapola ted throu gh a cu rv e-fitting rou tin e that compares resu lts with the parabolic ( ) two-step PTS heat diffusion model, and the th ickness m easu rem en t is enabled by the observ ation of ultrason ic wav es generated by femtosecond laser heatin g pu lses.
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