Variations of Thermal Conductivity with Porous Silicon Layer Thickness

Author(s):

Matthew H. Ervin and Aaron J. Henson

Abstract:

Porous silicon has many useful properties, which differ from those of bulk silicon. For instance, porous silicon has significantly lower thermal conductivity. This can be advantageous for some applications, but a problem for others. Therefore, understanding the thermal conductivity of porous silicon layers is important. We have discovered that the thicker the porous silicon layer, the lower its thermal conductivity. This may be due to an increase in its porosity due to an additional chemical etching mechanism or to increased phonon– phonon scattering as the temperature increases with the thickness of the thermally insulating porous silicon layer.