At delft institute of Microsystems and Nanoelectronics (DIMES), RF/microwave silicon devices have been implemented in a process that allows two-sided contacting of the devices. Dubbed the back-wafer-contacted Silicon On Glass (SOG) Substrate Transfer Technology (STT), that process was developed at DIMES. Those implementations were reviewed by Lis K. Nanver, Hugo Schellevis, Tom L.M. Scholtes, Luigi La Spina, Gianpaolo Lorito, Francesco Sarubbi, Victor Gonda, Milo Popadic, Koen Buisman, Leo C.N. de Vreede, Cong Huang, Silvana Milosavljevic, and Egbert J.G. Goudena.
This technology allows metal substrate lines to be placed on the low-loss glass substrate. At the same time, the resistive/capacitive parasitic elements of the silicon devices can be minimized by a direct two-sided contacting. A highly flexible design is achieved because the two-sided contacting eliminates the need for buried layers. See "Improved RF Devices for Future Adaptive Wireless Systems Using Two-Sided Contacting and AlN Cooling," IEEE Journal Of Solid-State Circuits, September 2009, p. 2322.
