In the last decade, devices manufactured with the SUMMiT ™ technology have demonstrated the capabilities of polysilicon surface micromachining. Currently Sandia is working on enhancements to this technology that utilize additional structural layers of silicon nitride to enable Microfluidics and BioMEMS applications. The addition of the silicon nitride layers allows the fabrication of microfluidic flow channels that are optically accessible (allowing observation) and insulating (allowing the placement of polysilicon electrodes at arbitrary locations in the flow channels). The goal of this effort is to provide functionality that is not feasible with other microfabrication technologies. The enhancements build on the key features of surface micromachining: manufacturability and compatibility with CMOS processing, which allow us to leverage the investment already made in microelectronics processing technology. Examples of devices fabricated using this technology include pumps, valves, and a cell manipulator.
(a) A flow channel with electrodes for creating/sensing electric and magnetic fields. Electrodes with varying shapes and spacing allow creation of almost any arbitrary field inside the channel for driving separations and in-channel synthesis. (b) Close-up SEM of polysilicon electrodes formed around the silicon nitride channcel structure.
Red blood cells flowing through the cellular manipulation device
(a) A flow channel with electrodes for creating/sensing electric and magnetic fields. Electrodes with varying shapes and spacing allow creation of almost any arbitrary field inside the channel for driving separations and in-channel synthesis. (b) Close-up SEM of polysilicon electrodes formed around the silicon nitride channcel structure.