There are many methods of depositing thin film materials: thermal evaporation, sputtering, electron or laser beam evaporation, chemical vapor deposition (CVD), and molecular beam epitaxy (MBE). A good survey of many of the deposition methods appears in the 1988 November and December issues of the MRS BULLETIN. One method not included in that survey, however, is metalorganic deposition (MOD), a powerful method for depositing a variety of materials.
Metalorganic deposition is not to be confused with metalorganic chemical vapor deposition (MOCVD), which is a gaseous deposition method. MOD is a nonvacuum, liquid-based, spin-on method of depositing thin films. A suitable organic precursor, dissolved in solution, is dispensed onto a substrate much like photoresist. The substrate is spun at a few thousand revolutions per minute, removing the excess fluid, driving off the solvent, and uniformly coating the substrate surface with an organic film a few microns thick. The soft metalorganic film is then pyrolyzed in air, oxygen, nitrogen, or other suitable atmosphere to convert the metalorganic precursors to their constituent elements, oxides, or other compounds. Figure 1 shows a schematic of the deposition process including a prebake and annealing (if necessary).