Memory devices having vertical transistors and methods for forming the same

Abstract

In certain aspects, a three-dimensional (3D) memory device includes a first semiconductor structure, a second semiconductor structure, and a bonding interface between the first semiconductor structure and the second semiconductor structure. The first semiconductor structure includes a peripheral circuit. The second semiconductor structure includes an array of memory cells and a plurality of bit lines coupled to the memory cells and each extending in a second direction perpendicular to the first direction. Each of the memory cells includes a vertical transistor extending in a first direction, and a storage unit coupled to the vertical transistor. A respective one of the bit lines and a respective storage unit are coupled to opposite ends of each one of the memory cells in the first direction. Two adjacent vertical transistors of the vertical transistors in the second direction are mirror-symmetric to one another. The array of memory cells is coupled to the peripheral circuit across the bonding interface.