New method of fabrication of suspended metallic single electron transistor (SET)

Charge sensing applications utilizing single electron transistors (SETs) as electrometers face challenges due to nearby background charge movements. In this study, we present an innovative fabrication method for creating suspended Al-AlO $x$-Al SETs positioned above a cavity. These suspended SETs exhibit significantly reduced flicker noise with $1 f α$ noise spectral density when compared to their substrate-based counterparts. This noise reduction can be attributed to the elimination of the substrate beneath the SET island. Consequently, our fabricated suspended SETs are highly suitable for demanding charge sensing applications and provide a promising platform for in-depth investigations into the sources of charge noise in such devices.