Method of making self-aligned high-frequency static induction transistor

摘要

A gate-source structure and fabrication method for a surface-gate static induction transistor. The method requires only one masking step during fabrication, thereby eliminating or minimizing mask registration problems during fabrication of the devices. The method and the device are characterized by a two-step etching process which forms T-shaped gate windows in layers of poly-crystalline silicon with different doping levels. The source region is formed during an annealing step from the layer with high doping level. During the annealing step, the gate regions are also formed from gate impurities implanted previously in the gate windows. The source structure and the gate structure are separated by a silicon dioxide protective layer.