A structure includes a metal nitride film of the form MN, where M is selected from the group consisting of Ga, In, AlGa, AlIn, and AlGaIn. The structure has at least one electrically conductive metal region that is formed within and from the metal nitride film by a thermal process driven by absorption of light having a predetermined wavelength. Single films comprised of AlN are also within the scope of this invention, wherein an Al trace or interconnect is formed by laser radiation of wavelength 248 nm so as to contact circuitry that exists under the film. Multilayered stacks of films are also within the scope of the teachings of this invention. In this case each film layer may be separately deposited and then illuminated to selectively form the desired electrical connection(s), which may also connect to conductive feature(s) in an underlying layer, or a plurality of metal nitride layers are stacked bottom to top in order of increasing electronic band gap energy value, and then the conductive features are written into selective ones of the layers by controlling the wavelength of the light to be absorbed in a desired layer. The teachings of this invention can be employed to fabricate fuses and anti-fuses enabling selective circuit customization, test and repair. Also disclosed is a technique for forming electrical resistors in a metal nitride layer by adjusting the electrical resistance of the metallization formed from the metal nitride film layer.