Ultra-thin ALD MGO membranes as mems transmission dynodes in a timed photon counter

Abstract

In this work we demonstrate how a novel single free electron detector 'Timed Photon Counter' (TiPC) may benefit from ultra-thin MgO transmission dynodes (tynodes). These membranes are fabricated through MEMS process technologies, with atomic layer deposition (ALD) as the most apt technique for growing films of good quality, with excellent control over thicknesses and extremely low surface roughness. Large area arrays of ultra-thin (5-25 nm) free-standing MgO membranes are fabricated and characterized to determine the optimal thickness for application of ALD MgO in TiPC. Supremacy of MgO over other materials previously considered, such as SiN, Al₂O₃, SiC, Si is verified. The exceptional mechanical (low stress in particular, -200 MPa), chemical and electrical properties of MgO make this material a very attractive candidate for numerous MEMS applications, as the MEMS transmission dynodes in the timed photon counter.