As the 3D NAND technology developing toward more and more stack layers, it is essential to shrink the gate length (Lg) and inter-gate space (Ls). However, one of key concerns of scaling Lg/Ls 3D NAND flash is post-cycling data retention characteristics. The impact of cycling induced intercell trapped charge on two primary charge loss mechanisms (vertical and lateral charge loss) was studied in this work. According to experimental analysis and TCAD simulation, it is found that, in vertically scaled 3D NAND, the vertical charge loss is deteriorated not only by the cycling induced tunnel oxide degradation (introducing interface/oxide traps), but also by the cycling induced intercell trapped charge (enhancing word-lines edge electric field), on account of the enhanced Poole-Frenkel effect and tunneling effect. On the other hand, the cycling induced intercell trapped charge can also suppress lateral charge migration. Therefore, the vertical charge loss, rather than the lateral charge migration, still can be the dominant factor for post-cycling retention characteristics in scaling Lg/Ls 3D NAND flash memory. INDEX TERMS 3D NAND flash memory, data retention, intercell trapped charge, PE cycling.

An all-solid-state AlGaN/GaN based ion-sensitive heterostructure field effect transistor (ISHFET) pH sensor was fabricated by integrating a noble metal (Au) quasi-reference electrode to improve the device stability when measuring the pH value of a small aqueous volume. In this paper, the influence of the size of the quasi-reference electrode against the stability of the pH readings was investigated. Through optimizing the size of the integrated quasi-reference electrode, the all-solid-state ISHFET pH sensor can sustain stable pH measurements for aqueous solutions of micro-litre size. A sensitivity of 55 mV/pH was achieved by the pH sensor at room temperature. Thus, the device may have potential uses in biomedical applications which require small volume pH measurements.

We demonstrate the enhancement of emission of InGaN/GaN multiple-quantum-well nanorods by nearly a factor of 2 by coupling them to localized surface plasmons of Au nano-particles (NPs). The Au NPs are fabricated in situ on the nanorods using a Ni/SiO2/Au/SiNx compound functional layer. This layer serves as a combination dry-etch mask for fabricating the nanorods and the Au NPs, as well as providing isolation necessary to prevent fluorescence quenching. Time-resolved photoluminescence measurements confirm that emission enhancement originates from the coupling.

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