Z. Lisa Zhang

SCREAM I: A single mask, single-crystal silicon, reactive ion etching process for microelectromechanical structures

A single-crystal slhcon, high aspect ratlo, low-temperature process sequence for the fabrlcatlon of suspended rmcroelectromechamcal structures (MEMS) usmg a smgle hthography step and reactwe Ion etching (RIE) IS presented The process IS called SCRJZAM I (single-crystal reactwe etchmg and metalhzatmn) SCREAM I IS a bulk mlcromachmmg process that uses RIE of a s~hcon substrate to fabricate suspended movable smgle-crystal s&on (SCS) beam structures Beam elements wth aspect ratios of 10 to 1 and widths rangmg from 0 5 to 4 0 Frn have been fabricated All process steps are low temperature (<3OO “C), and only conventronal sd~con fabrlcation tools are used photohthography, RIE, MIE, plasma-enhanced chemxal-vapor deposrtlon (PECVD) and sputter deposlhon SCREAM I IS a self-ahgned process and uses a smgle lithography step to define beams and structures srmultaneously as well as all necessary contact pads, electrIcal mterconnects and lateral capaators SCREAM I has been specifically deslgned for integration with standard Integrated cmxnt (IC) processes, so MEM deuces can be fabricated adjacent to prefabricated analog and dIgItal carcuitry In this paper we present process parameters for the fabncatlon of discrete SCREAM I devices We also discuss mask design rules and show micrographs of fabncated deuces

Integrated silicon process for microdynamic vacuum field emission cathodes

An integrated silicon process has been developed to produce self‐aligned gated field emitters on suspended and movable single‐crystal silicon beams. The field emitter fabrication process is compatible with an extended version of the single crystal reactive etching and metallization (SCREAM) process. The extended SCREAM process has been used to produce silicon stages with three‐dimensional (3D) translation (x,y,z) using integrated capacitive actuators and sensors. Here, we outline the field emitter fabrication process, the extended SCREAM process, and process integration. The integrated structural scheme includes the suspended field emitters integrated with the 3D translator. Electrical isolation and metal contacts are also incorporated with multiple, suspended silicon beams to provide electrical interconnects and isolation of the integrated tips, gate electrodes, actuators, and sensors. The stage with integrated field emitters, translators, isolation, and interconnects is a new approach to the 3D precisio...