A process for making a nozzle, the process comprising: forming a first opening having a first width in a top layer of a substrate ; forming a patterned layer of photoresist on the top surface of the substrate , the patterned layer of photoresist including a second opening, the second opening having a second width larger than the first width; reflowing the patterned layer of photoresist to form curved side surfaces terminating on the top surface of the substrate ; etching a second layer of the substrate through the first opening in the top layer of the substrate to form a straight-walled recess , the straight-walled recess having the first width, a bottom surface, and a side surface substantially perpendicular to the top surface of the substrate ; and after the straight-walled recess is formed, dry etching the curved side surface of the patterned layer of photoresist , the top layer of the substrate, and the second layer of the substrate, where the dry etching i) transforms the straight-walled recess into a funnel-shaped recess, the funnel-shaped recess includes a curved sidewall gradually smoothly joining a straight-walled lower portion of the recess or terminating on the bottom surface, ii) enlarges a portion of the straight-walled recess to a third width greater than the first width, and iii) enlarges the first opening in the top layer to a fourth width greater than the third width. forming a first opening having a first width in a top layer of a substrate ; forming a patterned layer of photoresist on the top surface of the substrate , the patterned layer of photoresist including a second opening, the second opening having a second width larger than the first width; reflowing the patterned layer of photoresist to form curved side surfaces terminating on the top surface of the substrate ; etching a second layer of the substrate through the first opening in the top layer of the substrate to form a straight-walled recess , the straight-walled recess having the first width, a bottom surface, and a side surface substantially perpendicular to the top surface of the substrate ; and after the straight-walled recess is formed, dry etching the curved side surface of the patterned layer of photoresist , the top layer of the substrate, and the second layer of the substrate, where the dry etching i) transforms the straight-walled recess into a funnel-shaped recess, the funnel-shaped recess includes a curved sidewall gradually smoothly joining a straight-walled lower portion of the recess or terminating on the bottom surface, ii) enlarges a portion of the straight-walled recess to a third width greater than the first width, and iii) enlarges the first opening in the top layer to a fourth width greater than the third width. i) transforms the straight-walled recess into a funnel-shaped recess, the funnel-shaped recess includes a curved sidewall gradually smoothly joining a straight-walled lower portion of the recess or terminating on the bottom surface, ii) enlarges a portion of the straight-walled recess to a third width greater than the first width, and iii) enlarges the first opening in the top layer to a fourth width greater than the third width. <EOS>