then removed in an oxygen plasma and the structure is annealed by heating to a temperature of from about 800 u00b0 to about 950 u00b0 preferably about 900 u00b0 c in an argon furnace for about 30 minutes annealing forms tantalum silicide i e tasi 2 by reacting with the underlying silicon layer the tantalum silicide layer is very conductive the tantalum silicide layer is then preferably protected with a thin layer of silicon oxide grown by either steam or dry oxidation it has been found in accordance with this invention that during annealing of the subject structures phosphorus diffuses from the polycrystalline silicon layer this increases the resistivity of the layer decreases the etch rate and markedly adversely affects the reproducibility of the etch hence reversing the order of these procedures as i have done produces a significant improvement in reproducibility the following examples further illustrate this invention it being understood that the invention is in no way intended to be limited to the details described therein in the examples all parts and percentages are on a weight basis and all temperatures are in degrees celsius unless otherwise stated a series of 100 single crystal silicon wafers were utilized as substrates the wafers were heated to 900 u00b0 in steam for 50 minutes to form a layer of silicon dioxide 200 nanometers thick on the surface the wafers were placed in a lpcvd reactor in a quartz tube which was heated to 580 u00b0 deposition of amorphous silicon was carried out at 350 mtorr pressure 200 cm 3 min.