Oxygen implantation through patterned masks: a method for forming insulated silicon device islands while maintaining a planar wafer surface

Abstract SIMOX (separation by implanted oxygen) is a recognized technology to produce silicon on insulator substrates. Laterally isolated device islands are formed by subsequent mesa etching or selective local oxidation of the silicon top layer. Alternatively, isolation can be achieved by using patterned masking layers in the implantation process, leading to continuous but nonplanar buried oxide layers. In order to ease device fabrication, it is desirable to achieve a planar wafer surface. Special test structures have been implanted with 200 keV oxygen to doses up to 2.4 × 10 18 O + cm −2 . The formation of TDI (total dielectric isolation) structures has been analyzed by Talystep and cross-sectional TEM. The successful formation of isolated islands in combination with a planar surface is demonstrated for an oxygen implantation through an oxide mask formed in a LOCOS process.