In one aspect, a method of forming a silicon-insulator layer is provided. The method includes arranging a silicon structure in a plasma etch process chamber and applying a plasma to the silicon structure in the plasma etch process chamber at a temperature of the silicon structure equal to or below 100° C. The plasma includes a component and a halogen derivate, thereby forming the silicon-insulator layer. The silicon-insulator layer includes silicon and the component. In another aspect, a semiconductor device is provided having a silicon-insulator layer formed by the method.