Simulating Selective and Non-Selective Epitaxy over Oxide Isolated Regions Using Athena
In certain cases, most notably in modern bipolar and SiGe HBT structures, epitaxial steps are performed after the oxide isolation structures have been already created. Thus the initial surface prior to epitaxy may contain regions of crystalline silicon, polysilicon or insulators, usually silicon dioxide. In the case of LOCOS isolation, the surface is also non-planar. In such epitaxial cases, epitaxy can be divided into two general types:-