Sang-eun Lee

Post-cycling data retention failure in multilevel nor flash memory with nitrided tunnel-oxide

Post-cycling data retention characteristics of a multilevel NOR flash memory with nitrided tunnel-oxide is presented. Results show that retention behavior is strongly related to the amount of interface trap generation rather than that of oxide trap, indicating detrapping from near interface trap is a major factor for threshold voltage shift. Process conditions including nitrogen concentration at the interface and subsequent annealing of nitrided tunnel-oxide by O2 are found to be related to the generation of interface trap and resultant postcycling retention.

Overcoming the fill factor limit of double sided buried contact silicon solar cells

The double sided buried contact (DSBC) silicon solar cells have consistently demonstrated output parameters superior to those of its single sided counterparts. This is because the high surface recombination velocity of the single sided cells was reduced to minimum by the rear floating junction in conjunction with high quality silicon dioxide. However, the somewhat lower fill factor (FF) exhibited by single sided illumination of the structure can disappear if the bifacial testing equipment is used to properly characterize the cells. A 2D simulation has shown that a rear illumination of only 0.2 sun in conjunction with 1 sun front illumination, is quite adequate to bias the rear junction to a high voltage required to maintain good fill factor. This article discusses the fill factor of double sided buried contact silicon solar cells under single and double sided illumination.

Highly manufacturable 90 nm NOR flash technology with 0.081 /spl mu/m/sup 2/ cell size

A manufacturable 90 nm NOR Flash technology has been developed with extremely small cell size of 0.081/spl mu/m/sup 2/, which is the smallest cell size of NOR cell, for high density code storage memory featuring with low voltage operation. The small cell size of 0.081/spl mu/m/sup 2/ is successfully achieved with three key main technologies such as an advanced KrF lithography with off-axis illumination system, appropriate dielectric thin film and junction scaling and optimized oxidation encroachment of inter-poly oxide nitride oxide (ONO) and tunnel oxide.

Characterizations of MONOS structures with a superthin nitride film for the low voltage NVSM using TSC techniques

TSC (thermally stimulated current) technique has been applied to investigate the characteristics of MONOS (metal-oxide-nitride-oxide-semiconductor) structures with superthin nitride film of 46 /spl Aring/ thick for the low voltage NVSM. A new discharging model bans been developed and formulated for analysis of TSC curves due to memory traps such as the blocking oxide-nitride interface trap and the nitride bulk trap. By best fitting method, the blocking oxide-nitride interface traps are found to be energetically distributed in the range of 1.17/spl sim/1.18 eV below the top of the nitride conduction band with a density of N/sub ON/=2.3/spl times/10/sup 15/ cm/sup -2/ eV/sup -1/. The discharging mechanism can be explained that the holes trapped in the blocking oxide-nitride interface traps, distributed uniformly in energy, are first thermally excited into the nitride valence band, then drifted to the nitride-tunneling oxide interface, and finally tunneled into the Si valence band to contribute to TSC.