| 摘要 |
Methods have been provided for forming both wide and narrow trenches on a high-aspect ratio microelectromechanical (MEM) device on a substrate including a substrate layer ( 126 ), an active layer ( 128 ), and a first sacrificial layer ( 130 ) disposed at least partially therebetween. The method includes the steps of forming a first trench ( 154 ), a second trench ( 156 ), and a third trench ( 152 ) in the active layer ( 128 ), each trench ( 154, 156, 152 ) having an opening and sidewalls defining substantially equal first trench widths, depositing oxide and sacrificial layers thereover and removing the oxide and sacrificial layers to expose the third trench ( 152 ) and form a fourth trench ( 190 ) in the active layer ( 128 ) from the first and the second trench ( 154, 156 ), the fourth trench ( 190 ) having sidewalls defining a second trench width that is greater than the first trench width.
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