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2011
Conference Paper
Titel
Diffusion and Characterization of Doped Patterns in Silicon from Prepatterned Boron- and Phosphorus-Doped Silicate Glasses
Abstract
n this work plasma-enhanced chemical-vapor deposition (PECVD) technology was used to deposit boron-doped silicate glasses (BSG) and phosphorus-doped silicate glasses (PSG) as solid diffusion sources with the goal of implementing locally doped p+- and n+-areas into monocrystalline silicon. For this purpose, several process sequences were carried out to pattern these layers before the diffusion step in a tube furnace using a wet chemical etch process in combination with an inkjet printed etch resist. The evaluated technology leads to a locally doped area on the wafer surface with a minimum feature size of approximately 100 Omega m. Boron-doped p+-areas in silicon with a sheet resistance of less than 25 Omega/sq (boron surface concentration NA>1019 cm-3) were achieved from BSG and phosphorus-doped n+-areas with a sheet resistance of less than 10 Omega/sq (phosphorus surface concentration ND>1020 cm-3) from PSG. An excellent electrical contacting behavior of physical vapor deposited aluminum to both doping types could be reached. Specific contact resistivities were measured to be below 5 m Omega cm2. This work establishes a highly flexible set of solid diffusion sources together with a high precision structuring method, allowing for well controlled local doping of silicon.
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