Browsing by Author "Cimen, F."
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Item Open Access Enhanced memory effect via quantum confinement in 16 nm InN nanoparticles embedded in ZnO charge trapping layer(AIP Publishing, 2014) El-Atab, N.; Cimen, F.; Alkis, S.; Ortac, B.; Alevli, M.; Dietz, N.; Okyay, Ali Kemal; Nayfeh, A.In this work, the fabrication of charge trapping memory cells with laser-synthesized indium-nitride nanoparticles (InN-NPs) embedded in ZnO charge trapping layer is demonstrated. Atomic layer deposited Al2O3 layers are used as tunnel and blocking oxides. The gate contacts are sputtered using a shadow mask which eliminates the need for any lithography steps. High frequency C-Vgate measurements show that a memory effect is observed, due to the charging of the InN-NPs. With a low operating voltage of 4 V, the memory shows a noticeable threshold voltage (Vt) shift of 2 V, which indicates that InN-NPs act as charge trapping centers. Without InN-NPs, the observed memory hysteresis is negligible. At higher programming voltages of 10 V, a memory window of 5 V is achieved and the Vt shift direction indicates that electrons tunnel from channel to charge storage layer. © 2014 AIP Publishing LLCItem Open Access Enhanced memory effect with embedded graphene nanoplatelets in ZnO charge trapping layer(AIP Publishing, 2014) El Atab, B.; Cimen, F.; Alkis, S.; Okyay, Ali Kemal; Nayfeh, A.A charge trapping memory with graphene nanoplatelets embedded in atomic layer deposited ZnO (GNIZ) is demonstrated. The memory shows a large threshold voltage Vt shift (4 V) at low operating voltage (6/-6 V), good retention (>10 yr), and good endurance characteristic (>104 cycles). This memory performance is compared to control devices with graphene nanoplatelets (or ZnO) and a thicker tunnel oxide. These structures showed a reduced Vt shift and retention characteristic. The GNIZ structure allows for scaling down the tunnel oxide thickness along with improving the memory window and retention of data. The larger Vt shift indicates that the ZnO adds available trap states and enhances the emission and retention of charges. The charge emission mechanism in the memory structures with graphene nanoplatelets at an electric field E ¥ 5.57 MV/cm is found to be based on Fowler-Nordheim tunneling. The fabrication of this memory device is compatible with current semiconductor processing, therefore, has great potential in low-cost nano-memory applications. © 2014 AIP Publishing LLC.Item Open Access Thin-film ZnO charge-trapping memory cell grown in a single ALD step(Institute of Electrical and Electronics Engineers, 2012-10-26) Oruc, F. B.; Cimen, F.; Rizk, A.; Ghaffari, M.; Nayfeh, A.; Okyay, Ali KemalA thin-film ZnO-based single-transistor memory cell with a gate stack deposited in a single atomic layer deposition step is demonstrated. Thin-film ZnO is used as channel material and charge-trapping layer for the first time. The extracted mobility and subthreshold slope of the thin-film device are 23 cm2/V · s and 720 mV/dec, respectively. The memory effect is verified by a 2.35-V hysteresis in the $I\rm drain- $V\rm gate curve. Physics-based TCAD simulations show very good agreement with the experimental results providing insight to the charge-trapping physics.