by applying e g by sputtering evaporating or other means of depositing or growing a metallization layer onto the wafer i e onto exposed portions of layers 80 and 82 a photoresist is applied and patterned to portions of the metallization layer to mask the desired contact area an aluminum etchant is then used to remove unwanted aluminum the photoresist is then removed e g with oxygen plasma at 68 a relatively thick photoresist is applied to exposed surfaces of the wafer and prebaked the photoresist is patterned 70 into the desired topography of device 20 e g fig3 at 72 a shallow etchant is applied to remove the exposed portions of device layer 80 a second e g vaporized etchant is then applied to remove the newly exposed portions of oxide layer 82 a shallow etchant is again applied to remove the exposed portions of second device layer 80 u2032 at 74 the underside of the wafer is patterned with a photoresist and etched to the oxide layer 82 u2032 at 76 a vaporized etchant e g hf vapor is used to remove exposed portions of oxide layer 82 u2032 at 78 the photoresist is removed e g by use of oxygen plasma to produce completed device 20 the following illustrative example is intended to demonstrate certain aspects of the present invention it is to.