Field dependence of evaporated ion species in field-induced chemical etching of tungsten with oxygen and nitrogen

We investigated field evaporated ion species in field-induced chemical etching with oxygen and tungsten by using in-situ atom probe. The range of evaporation field of products at the tungsten surface in oxygen etching was broader than that in nitrogen etching. The difference in field strength for field evaporation of tungsten oxide and nitride causes the shape of the emitter shape after the etching process.