Semiconductor structures and methods are provided for a semiconductor device (40) employing a superjunction structure (41) and overlying trench (91) with embedded control gate (48). The method comprises, forming (52-6, 52-9) interleaved first (70-1, 70-2, 70-3, 70-4, etc.) and second (74-1, 74-2, 74-3, etc.) spaced-apart regions of first (70) and second (74) semiconductor materials of different conductivity type and different mobilities so that, in a first embodiment, the second semiconductor material (74) has a higher mobility for the same carrier type than the first semiconductor material (70), and providing (52-14) an overlying third semiconductor material (82) in which a trench (90, 91) is formed with sidewalls (913) having thereon a fourth semiconductor material (87) that has a higher mobility than the third material (82), adapted to carry current (50) between source regions (86), through the fourth (87) semiconductor material in the trench (91) and the second semiconductor material (74) in the device drift space (42) to the drain (56). In a further embodiment, the first (70) and third (82) semiconductor materials are relaxed materials and the second (74) and fourth (87) semiconductor materials are strained semiconductor materials.