Optimized inductor and low-pass filter with low substrate loss on OPS/PS interlayer

Oxidized porous silicon/porous silicon (OPS/PS) has been introduced as a low-loss substrate for an on-chip LC low-pass filter (LPF). The LPF is optimally designed with midband insertion loss (MIL) of -4.5dB and nominal cutoff frequency at 900MHz. The fabrication of the LPF based OPS/PS is in prevailing CMOS process. Experiments show that the performance of the LPF has been greatly improved with MIL of -4.54dB that meets the designed value quite well. And in comparison with MIL of LPF on SiO2/Si (8Ω cm), MIL with the proposed interlayer is lowered by 8dB, which implies that the microwave loss resulting from the substrate part can be substantially suppressed by introducing OPS/PS.