Method of Forming Split Silicon Mesas
Original Publication Date: 1986-Nov-01
Included in the Prior Art Database: 2005-Mar-09
A method is described in which mesas of substrate single crystal silicon are formed having a deep, oxide-filled, narrow divider. The divider has a width dimension which is smaller than can be formed by lithography. Referring to Fig. 1, silicon (Si) substrate 2 is first oxidized to result in a thin blanket coating of SiO2 4. A thin silicon nitride (Si3N4) layer 6 is then deposited. A thick (1 um) polysilicon layer is deposited over all. By photo processing and reactive ion etching (RIE), the polysilicon 8 is formed into blocks having 1 um widths and 1 um spacing between blocks, the present state of lithographic art in manufacturing. Next, a conformal coating of SiO2 10 is applied to a thickness of 0.4 um, leaving a gap dimension d = 0.2 um.