Micro-electromechanical system (MEMS) devices and methods of manufacture thereof are disclosed. In one embodiment, a MEMS device includes a first semiconductive material and at least one trench disposed in the first semiconductive material, the at least one trench having a sidewall. An insulating material layer is disposed over an upper portion of the sidewall of the at least one trench in the first semiconductive material and over a portion of a top surface of the first semiconductive material proximate the sidewall. A second semiconductive material or a conductive material is disposed within the at least one trench and at least over the insulating material layer disposed over the portion of the top surface of the first semiconductive material proximate the sidewall.