Porous silicon as a substrate for the integration of high performance on-chip antennas

In this paper we report on the application of low-loss and low-permittivity thick porous Si (PSi) layer as a local substrate on bulk Si wafer for the on-chip integration of millimeter wave antennas (~50 GHz). The necessary PSi area, thickness and dielectric permittivity for optimized performance of the dipole antenna are investigated through 3D simulations. The simulated antenna is fabricated on a locally formed 150 μm thick PSi layer and compared to an identical antenna on bulk low resistivity Si (1-10 Ω.cm). It was found that the gain of the antenna on PSi was improved from -24 dBi on bulk Si to -13 dBi on the PSi layer. Good agreement between measurements and simulations was observed.