Electrical performance optimization of a silicon-based EUV photodiode with near-theoretical quantum efficiency

Ultrashallow Si p⁺n photodiodes fabricated in a pure-boron chemical-vapor-deposition (CVD) technology are investigated with respect to the relation between sensitivity to extreme-ultraviolet light and electrical performance (dark current and response time). The photodiodes are covered with a boron layer (B-layer diodes) which can be nanometer thin, allowing a quantum efficiency close to the theoretical maximum in the EUV spectral range. The experimental results presented here show that, by modifying the diode structure, both reproducible low dark current and short response time can be realized without any significant drop of the EUV sensitivity.