A dielectric layer comprises lanthanum, aluminum and oxygen and is formed between two conductors or a conductor and substrate. In one embodiment, the dielectric layer is graded with respect to the lanthanum or aluminum. In another embodiment, an insulating layer is formed between the conductor or substrate and the dielectric layer. The dielectric layer can be formed by atomic layer chemical vapor deposition, physical vapor deposition, organometallic chemical vapor deposition or pulsed laser deposition.