Microwave-CVD Diamond Protective Coating for 3D Structured Silicon Microsensors

Abstract

In this work a multi-step nucleation-deposition MW-CVD process is presented developed for contiguous covering of 3 dimensional Si bulk micromachined structures. A correlation between the nucleation rate and the electric field distribution over the 3D surface was established. The layer integrity was characterised by scanning electron and atomic force microscopy. The pinhole density of the layers was measured by conventional alkaline underetching method. This technique is primarily suitable for the characterisation of layers deposited on flat surfaces and was used as a reference for the electrochemical method applied for the non-planar surfaces. Application of the protective coating was demonstrated on the surface of a Si capacitive pressure sensor chip.

Micro-hotplates for thermal characterisation of structural materials of MEMS

“…The diamond coated filament structure (Version 2) also utilizes the porous silicon micromachining [4] technique in combination with a three-step multilayer deposition (diamond/poly-crystalline silicon/diamond), doping and appropriate patterning. The material of the filament is preferably poly-crystalline silicon in order to easy adaptation of the Selective Area Deposition (SAD) technique used for patterning [5]. The main steps of the process sequence are presented by Fig.…”

Micro-hotplates for thermal characterisation of structural materials of MEMS

“…The material of the filament is preferably poly-crystalline silicon in order to easy adaptation of the Selective Area Deposition (SAD) technique used for patterning [5]. The main steps of the process sequence are presented by Fig.…”