The invention includes methods of forming circuit devices. A metal-containing material comprising a thickness of no more than 20 .ANG. (or alternatively comprising a thickness resulting from no more than 70 ALD cycles) is formed between conductively-doped silicon and a dielectric layer. The conductively-doped silicon can be n-type silicon and the dielectric layer can be a high-k dielectric material. The metal-containing material can be formed directly on the dielectric layer, and the conductively-doped silicon can be formed directly on the metal-containing material. The circuit device can be a capacitor construction or a transistor construction. If the circuit device is a transistor construction, such can be incorporated into a CMOS assembly. Various devices of the present invention can be incorporated into memory constructions, and can be incorporated into electronic systems.