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Abstract: In this work, we report a non-destructive approach, which is based on the spectroscopic ellipsometry (SE) and a multi-layer model, to calculate the depth profiling of the dielectric functions of SiO2 films containing Si nanocrystals (nc-Si) synthesized by ion beam technique. Each sub-layer of SiO2 film containing nc-Si is represented by Maxwell-Garnett effective medium approximation (EMA). Then the nc-Si dielectric functions are extracted from the best fittings of SE results. Finally, the dielectric functions of each sub-layer of SiO2 containing nc-Si are calculated with Maxwell-Garnett EMA using the previously extracted information of nc-Si, and thus the depth profile of dielectric functions for the SiO2 thin film containing the nc-Si is obtained. [Copyright &y& Elsevier]

Abstract: In this work, we have investigated the performance and reliability of a Flash memory based on silicon nanocrystal synthesized with very-low energy ion beams. The devices are fabricated with a conventional CMOS process and the size of the nanocrystal is ∼4 nm as determined from TEM measurement. Electrical properties of the devices with a tunnel oxide of either 3 nm or 7 nm are evaluated. The devices exhibit good endurance up to 105 W/E cycles even at the high operation temperature of 85 °C for both the tunnel oxide thicknesses. For the thicker tunnel oxide (i.e., the 7-nm tunnel oxide), a good retention performance with an extrapolated 10-year memory window of ∼0.3 V (or ∼20% of charge lose after 10 years) is achieved. However, ∼70% of charge loss after 10 years is expected for the thinner tunnel oxide (i.e., the 3-nm tunnel oxide). [Copyright &y& Elsevier]

Abstract: In this work, we have investigated the capacitance–voltage (C–V) and conductance–voltage (G–V) characteristics of silicon nanocrystals (nc-Si) distributed in the gate oxide very near the SiO2/Si interface of a Metal-Oxide-Semiconductor (MOS) structure. The MOS structure is found to be sensitive to only the positive voltage stress from which charging of the nanocrystals causes a negative flatband voltage shift. At the same time, a large conductance peak is observed due to the energy loss via the neutral-nanocrystal paths near the SiO2/Si interface. Besides, breakdown of the dielectric film containing the nc-Si is also observed from the G–V characteristic. [Copyright &y& Elsevier]

Abstract: In this work, the unique synthesis of mechanically milled silicon nanocrystals (Si nc) embedded in tetraethylorthosilicate (TEOS) thin films is reported. The Si nc are required to be synthesized externally via inexpensive mechanical milling before it is mixed with the TEOS solution for spin coating. Si nc with a range of sizes, from 10 to 25nm, have been synthesized using mechanical milling. These milled Si nc and milled Si nc embedded in TEOS thin film are characterized by differential thermal analysis (DTA), Raman spectroscopy and photoluminescence excitation (PLE). The defects, such as non-bridging oxide hole centers (NBOHCs), in amorphous SiO2 are found to be the most probable dominant mechanism for the PL of milled Si nc embedded in films. The milled Si nc embedded in TEOS thin film is further developed into MOS capacitor. Charge trapping in Si nc with a V FB shift of 0.4V is observed. [Copyright &y& Elsevier]