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Updated: Jan 25, 2026

Metal-Assisted Electrochemical Nanoimprinting of Porous and Solid Silicon Wafers
Published on: February 8, 2022
Investigation of ultrasonic absorption in the MHz frequency range by silicon substrates with a built-in porous
J Lascaud1, T Defforge1, G Gautier1
1GREMAN UMR 7347, Université de Tours, CNRS, INSA Centre Val de Loire, 16 rue Pierre et Marie Curie, 37071 Tours cedex 2, France.
Abstract:
The present study is focused on the development and characterization of an innovative substrate to optimize the axial resolution of ultrasonic transducers on a silicon substrate that is dedicated to ultrasound imaging. The substrate must efficiently dampen wave propagation to avoid degradation of the axial resolution of ultrasound images. In this study, the proposed approach implements a silicon substrate with a built-in acoustic damping layer composed of porous silicon. Porous silicon layers with thicknesses of less than 100 µm and porosities varying from 27% to 62% were fabricated, and their substrate resonances were characterized. The experimental results obtained in the frequency range from 6 MHz to 10 MHz show that the substrate acoustic damping is controlled by adjusting the characteristics of the porous silicon layer; a significant damping of 70% is demonstrated with only 70 µm of porous silicon.
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