The present disclosure describes a method for forming a hard mask on a transistor's gate structure that minimizes gate spacer loss and gate height loss during the formation of self-aligned contact openings. The method includes forming spacers on sidewalls of spaced apart gate structures and disposing a dielectric layer between the gate structures. The method also includes etching top surfaces of the gate structures and top surfaces of the spacers with respect to a top surface of the dielectric layer. Additionally, the method includes depositing a hard mask layer having a metal containing dielectric layer over the etched top surfaces of the gate structures and the spacers and etching the dielectric layer with an etching chemistry to form contact openings between the spacers, where the hard mask layer has a lower etch rate than the spacers when exposed to the etching chemistry.