Abstract: A method is provided for forming a monolithically integrated optical filter, for example, a Fabry-Perot filter, over a substrate (10). The method comprises forming a first mirror (16) over the substrate (10). A plurality of etalon material layers (32, 34, 36, 38) are formed over the mirror (16), and a plurality of etch stop layers (42, 44, 46) are formed, one each between adjacent etalon material layers (32, 34, 36, 38). A photoresist is patterned to create an opening (54) over the top etalon material layer (38) and an etch (56) is performed down to the top etch stop layer (46). An oxygen plasma (58) may be applied to convert the etch stop layer (46) within the opening (54) to silicon dioxide (57). The photoresist patterning, etching, and applying of an oxygen plasma may be repeated as desired to obtain the desired number of levels (82, 84, 86, 88). A second mirror (72) is then formed on each of the levels (82, 84, 86, 88).

Abstract: A method for preparing a semiconductor substrate surface (28) for semiconductor device fabrication, includes providing a semiconductor substrate (20) having a pure Ge surface layer (28) or a Ge-containing surface layer (12), such as SiGe. The semiconductor substrate (20) is cleaned using a first oxygen plasma process (14) to remove foreign matter (30) from the surface (28) of the substrate (20). The substrate surface (28) is next immersed in a hydrochloric acid solution (16) to remove additional foreign matter (30) from the surface (28) of the substrate (20). The immersion step is followed by a second oxygen plasma etch process (18), passivate the surface with a passivation layer (34), and provide for an atomically smooth surface for subsequent epitaxial or gate dielectric growth.