A semiconductor process and apparatus use a predetermined sequence of patterning and etching steps to etch a gate stack (62) formed over a substrate (11) and a first spacer structure (42), thereby forming etched gate structures (72, 74) that are physically separated from one another but that control a substrate channel (71) subsequently defined in the substrate (11) by source/drain regions (82, 102, 84, 104) that are implanted around the etched gate structures (72, 74). Depending on how the first spacer structure (42) is positioned and configured, the channel (71) may be controlled to provide either a logical AND gate (100) or logical OR gate (200) functionality.