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Md. Hanif Ali

Publications and source records attributed to Md. Hanif Ali.

2 recordsLinked to original sources

Defect-Aware Physics-Based Compact Model for Ferroelectric nvCap: From TCAD Calibration to Circuit Co-Design

Ferroelectric non-volatile capacitance-based memories enable non-destructive readout and low-power in-memory computing with 3D stacking potential. However, their limited memory window (1-10 fF/{\mu}m) requires material-device-circuit co-optimization. Existing compact models fail to capture the physics of small-signal capacitance, device variability, and cycling degradation, which are critical parameters for circuit design. In non-volatile capacitance devices, the small-signal capacitance difference of the polarization states is the key metric. The majority of the reported compact models do not incorporate any physical model of the capacitance as a function of voltage and polarization. We present a physics-based compact model that captures small-signal capacitance, interface and bulk defect contributions, and device variations through multi-scale modeling combining experimental data, TCAD simulations, and circuit validation. Based on this methodology, we show optimized memory read-out with +/- 5 mV sense margin and impact of device endurance at the circuit level. This work presents a comprehensive compact model which enables the design of selector-less arrays and 3D-stacked memories for compute-in-memory and storage memory.

cs.ET

Interlayer-engineered local epitaxial templating induced enhancement in polarization (2P$_r$ > 70$μ$C/cm$^2$) in Hf$_{0.5}$Zr$_{0.5}$O$_2$ thin films

In this work, we report a high remnant polarization, 2Pr >70$μ$C/cm$^2$ in thermally processed atomic layer deposited Hf0.5Zr0.5O2 (HZO) film on Silicon with NH3 plasma exposed thin TiN interlayer and Tungsten (W) as a top electrode. The effect of interlayer on the ferroelectric properties of HZO is compared with standard Metal-Ferroelectric-Metal and Metal-Ferroelectric-Semiconductor structures. X-Ray Diffraction shows that the Orthorhombic (o) phase increases as TiN is thinned. However, the strain in the o-phase is highest at 2 nm TiN and then relaxes significantly for the no-TiN case. HRTEM images reveal that the ultra-thin TiN acts as a seed layer for the local epitaxy in HZO potentially increasing the strain to produce a 2X improvement in the remnant polarization. Finally, the HZO devices are shown to be wake-up-free, and exhibit endurance >10^6 cycles. This study opens a pathway to achieve epitaxial ferroelectric HZO films on Si with improved memory performance.

cond-mat.mtrl-sci