Silicon Carbide Delta-Doped Structures Formed by 'Pulse Doping' Technique in the Vertical Hot Wall Type CVD System

摘要

Delta-doped layers of silicon carbide (SiC) have been investigated by our original "Pulse Doping" technique during epitaxial growth in the vertical hot wall type chemical vapor deposition (CVD) system. This CVD system was equipped with a graphite crucible in which the substrate was set surface-down. The dopant gases are intermittently introduced and managed utilizing the pulse valve, which can open and close within <10μs. Carrier concentrations of the uniformly doped layers were precisely controlled by variation of the period of this valve. Moreover, "Pulse Doping" technique enabled formation of very abrupt interface between doped and undoped layers. The delta-doped layers with narrow width less than 20nm were successfully formed. Furthermore, the stratified structures of the delta-doped layers were achieved in the SiC epitaxial films for the first time.