A different way of performing picosecond ultrasonic measurements in thin transparent films based on laser-wavelength effects

Arnaud Devos (1) , Renaud Cote (1) , Grégory Caruyer (2) , Arnaud Lefevre (3)

1 IEMN - Institut d’Électronique, de Microélectronique et de Nanotechnologie - UMR 8520
2 ST-CROLLES - STMicroelectronics [Crolles]
3 CEA-LETI - Commissariat à l'énergie atomique et aux énergies alternatives - Laboratoire d'Electronique et de Technologie de l'Information

We present a way of using picosecond ultrasonics to simultaneously get the thickness and elastic properties of thin dielectric layers. This is based on the use of a blue probe which is shown to improve the detection of acousto-optic oscillations in the dielectric from which the sound velocity can be measured from the refractive index. At the same wavelength a strong response of the silicon is used to detect the arrival of the acoustic pulse. We apply this scheme to various materials deposited on silicon substrates.

Domaines: Physique [physics]

Arnaud Devos, Renaud Cote, Grégory Caruyer, Arnaud Lefevre. A different way of performing picosecond ultrasonic measurements in thin transparent films based on laser-wavelength effects. Applied Physics Letters, 2005, 86, pp.211903. ⟨10.1063/1.1929869⟩. ⟨hal-00124474⟩