A preferred embodiment microplasma device includes first and second substrates. An electrode array is disposed on the first substrate. Cavities are formed in the second substrate by laser micromachining, etching, or by chemical (wet or dry) etching and the second substrate is overlaid on the electrode array. The inter-electrode spacing and electrode width are set so that each cavity has at least one pair of electrodes underneath it to excite a microplasma discharge in the cavity. A need to precisely register the two substrates is avoided.