Capacitors and methods of forming the same include forming an oxygenated dielectric layer on a first conductive layer. A second conductive layer is formed on the oxygenated dielectric layer. The oxygenated dielectric layer is heated to release the oxygen from the oxygenated dielectric layer and to oxidize the first and second conductive layers at interfaces between the dielectric layer and the first and second conductive layers, forming barrier layers at the interfaces.