Various RF Substrate Solutions for 22 nm FD-SOI Technology Targeting Cryogenic Applications

In this work, RF performance of standard and various high-resistivity (HR) substrates, namely including PN passivated ones, are evaluated at both room and cryogenic temperatures via the small-signal measurements of different passive elements, i.e. CPW and TFMS lines. The effective resistivity and the propagation losses of transmission lines are extracted. Degradation of substrates losses and an improvement of metallic losses at low temperature are shown. Finally, the PN interface passivation solution is evaluated for the first time to the authors' best knowledge, at cryogenic temperature and an improvement of effective resistivity by at least a factor $7\mathbf{x}$ is observed over the HR substrate without any passivation solution.