Novel Micro Capacitive Inclinometer with Oblique Comb Electrode and Suspension Spring Aligned Parallel to {111} Vertical Planes of (110) Silicon

A novel high resolution micro capacitive inclinometer has been developed using (110) silicon. KOH crystalline wet etching was employed after silicon deep reactive ion etching (DRIE) to reduce morphologic defects on the sidewalls of oblique comb electrodes aligned parallel to vertical {111} plane. Suspension springs are also parallel to other vertical {111} plane to secure the width during KOH wet etching. The sensitivity (pF/deg) was increased because the oblique comb electrodes change both the overlapped area and gap during operation. The capacitance changed from -0.8 to 0.8 pF for -90deg -90deg and resolution was estimated at 0.18deg or less for plusmn80deg.