A capacitive surface-micromachined sensor suitable for the measurement of liquid and gas pressures was fabricated. The structure consists of a polysilicon stationary electrode suspended 0.7 /spl mu/m above a 20-/spl mu/m-thick lightly doped silicon diaphragm formed by a patterned etch stop. The a priori patterning of the buried etch stop yields diaphragm widths independent of wafer thickness variations with excellent alignment. The design described here has a pressure range of 100 PSI, a nominal capacitance of 3.5 pF with a full scale span of 0.8 pF, and a temperature coefficient of 100 ppm/spl deg/C/sup -1/. Each device, including a matched reference capacitor, occupies 2.9 mm/sup 2/, yielding approximately 2000 devices per 100-mm wafer.
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机译:制造了适合于测量液体和气体压力的电容式表面微机械传感器。该结构由多晶硅固定电极组成,该多晶硅固定电极悬吊在通过图案化蚀刻停止层形成的20 / splμ/ m厚轻掺杂硅膜片上方0.7 / spl mu / m的位置。掩埋蚀刻停止层的先验图案产生的膜片宽度与晶圆厚度变化无关,具有出色的对准性。此处描述的设计的压力范围为100 PSI,标称电容为3.5 pF,满量程跨度为0.8 pF,温度系数为100 ppm / spl deg / C / sup -1 /。每个器件,包括一个匹配的基准电容器,占2.9 mm / sup 2 /,每100毫米晶片大约可生产2000器件。
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