Abstract: The specification describes a process for fabricating semiconductor devices and circuits in which lateral geometry dimensions determining the performance level of the device or circuit are extremely small. In this process electron beam microfabrication techniques are used to define these extremely small dimensions. The complete fabrication process uses standard photolithography for the definition of some of the device geometry and mask patterns, and partitioning of pattern definition between electron beam microfabrication and standard photolithography is utilized according to pattern resolution requirements, and is optimized for the highest yield-throughout product.