Substrate-coupling effect in BiCMOS technology for millimeter wave applications

This paper presents a detailed analysis of substrate coupling effects. Two types of coupling are considered. (i) Coupling from the device to the substrate and (ii) coupling between two neighboring devices. To assess the substrate coupling effect, specific test-structures have been designed for the mmW characterization. Various devices dimensions and distance between two neighboring devices have been fabricated for investigation. In addition, the associated deembedding structures have also been added on the test-structure such as the open, short, open and open-pad structures. Finally, S parameters measurements are performed up to 110 GHz and the substrate-coupling is investigated. To validate the analysis, Sentaurus TCAD simulations are used. A comparison between the S-parameters measurements and TCAD results is given. Finally, a scalable compact model based on lumped elements is proposed for the circuit design in the sub-THz range.