The paper presents design, analysis and fabrication of novel silicon-based, low power, non-volatile NEMS logic switches. Non-volatility is achieved by exploiting the Casimir effect and the van der Waals force at mechanical contact between an in-plane, laterally moveable transistor channel and two opposing side gates. Mechanical symmetry is implemented in the design for switching to be energy reversible. Device operation is simulated by coupling close range interatomic force calculations with 3D FEM simulation. 'On' and 'Off' transistor states are maintained by controlling the surface area of mechanical contact between the beam and the gate electrode. To achieve this, two nano-stiction state controller designs are proposed for experimental comparison. Preliminary devices have been successfully fabricated using ebeam lithography to verify minimum feature size of proposed structures.