ABSTRACT
The issue of the interaction of free charge carriers in the substrate with RF signals propagating through passive and active devices is well known [1]. This causes signal and efficiency losses, harmonic or intermodulation distortion, and crosstalk between devices. High-porosity, micro-porous silicon has been proposed as a potential solution to this problem [2], because the lateral dimensions of the remaining inter-pore silicon can be made small enough to induce a complete depletion, resulting in some cases in an effective resistivity above 100 kOhm. cm. Therefore, porous silicon is a promising technology for applications like low-noise amplifiers or RF switches. For higher power density devices (such as power amplifiers), the thermal conductivity of porous silicon may be too low to dissipate the power of the losses.
