1,213,069. Semi-conductor devices. SEMIKRON GES. FUR GLEICHRICHTERBAU UND ELEKTRONIK m.b.H. 2 May, 1968, No. 20767/68. Heading H1K. The reverse characteristics of semi-conductor devices are stabilized by a process in which the surface of the device is contacted with a mixture containing an organic compound which is able to act as a co-ordinating getter for impurities on the surface and containing a prepolymer or the components of a polymer, the system being heated at temperatures of up to 200� C. for from 2-24 hours to complete polymerization and effect gettering. The mixture may be a liquid which is applied to the surface by usual methods or (when using a prepolymer in the mixture) may be a solid preform fitted to the body. Polymers formed may be silicone resins, polyester resins, glyptal resins, or epoxy resins. Gettering compounds suggested are hydroxy- and amino-anthraquinones, xanthenes, phthalocyanines, and azo-dyestuffs.