Embodiments of three-dimensional (3D) memory devices with stacked device chips using interposers and fabrication methods thereof are disclosed. In an example, a 3D memory device includes first and second device chips and an interposer therebetween. The first device chip includes a peripheral device and a first chip contact on a surface of the first device chip and electrically connected to the peripheral device. The second device chip includes an alternating conductor/dielectric stack, a memory string extending vertically through the alternating conductor/dielectric stack, and a second chip contact on a surface of the second device chip and electrically connected to the memory string. The interposer includes an interposer substrate, first and second interposer contacts on opposite surfaces of the interposer and electrically connected to one another through the interposer substrate. The first and second interposer contacts are attached to the first and second chip contacts, respectively.