Flexible RF/Microwave Switch-PIN Diodes Using Single-Crystal Si-Nanomembranes

We report, to the best of our knowledge, the first realization of flexible single-crystal Si PIN diodes that are monolithically integrated on low-cost, low-temperature, flexible plastic substrate. 200-nm thin Si (001) nanomembrane is deprived from silicon-on-insulator (SOI) substrate after selective n-and p-type doping on the designated regions. The detailed fabrication of Si-nanomembrane (SiNM) PIN diodes on plastic substrate is described. The flexible SiNM PIN diodes demonstrate typical rectifying characteristics. S-parameter measurements on these PIN diodes show an insertion loss of less than 1.7 dB with isolation higher than 20 dB from DC up to 5 GHz at low bias conditions.