This paper is concerned with the elliptic equation −∆u = λ (a−u) p in a connected, bounded C 2 domain Ω of R N subject to zero Dirichlet boundary conditions, where λ > 0, N ≥ 1, p > 0 and a : Ω → [0, 1] vanishes at the boundary with the rate dist(x, ∂Ω) γ for γ > 0.When p = 2 and N = 2, this equation models the closed Micro-Electromechanical Systems devices, where the elastic membrane sticks the curved ground plate on the boundary, but insulating on the boundary. The function a shapes the curved ground plate.Our aim in this paper is to study qualitative properties of minimal solutions of this equation when λ > 0, p > 0 and to show how the boundary decaying of a works on the minimal solutions and the pull-in voltage. Particularly, we give a complete analysis for the stability of the minimal solutions.