Memory characteristics of MOSFET with silicon nanoclusters formed using a pulse-type gas-feeding technique in the LPCVD system
The digital gas-feeding method was used in this study, with Si2H6 as the source gas, in a low-pressure chemical-vapor deposition system, to grow Si nanoclusters with high densities and uniform sizes. The densities of the Si nanoclusters rose to 71011cm?2, and their sizes slightly changed at about 7nm based on the frequency of gas-pulse feeding in the digital process. MOSFETs containing Si nanoclusters as a floating gate in the gate stack were fabricated, and the various nonvolatile-memory characteristics of MOSFET were investigated. The total threshold voltage shift of 3.7V was achieved, and the program/erase times were found to be 5?s/50ms when the program/erase voltages were +18/?20V, respectively. The charge-storage memory window was extrapolated over 1year to be 1.5V in the retention measurements of the fabricated Si nanocluster floating-gate memory device.
digital gas-feeding si nanocluster flash memory nanocrystal floating-gate memory nonvolatile memory