The Influence of PSC on SAW Devices Based on SiC Substrates

Surface acoustic wave (SAW) devices based on silicon carbide (SiC) substrates have been widely studied. In this paper, we discuss the impact of the parasitic surface conductivity (PSC) effect caused by fixed charges at the SiO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf>/SiC interface on SAW device performance. We examine the effects of PSC on carrier motion in high-purity (HP) SiC, vanadium (V)-doping SiC, and poly-Si/SiC structures. Additionally, the positions of trap levels (Et) and the Fermi level (Ef) have the greatest impact on the suppression of the PSC effect. Furthermore, the effective resistivity (R<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">eff</inf>) of these three structures and its impact on SAW device performance are also discussed. This work provides important insights for suppressing PSC in Si-based or SiC-based radio frequency (RF) devices.