Sub-10 nm HfZrO ferroelectric synapse with multiple layers and different ratios for neuromorphic computing.

To break the von Neumann bottleneck, emerging non-volatile memories have gained extensive attention in hardware implementing neuromorphic computing. The device scaling with low operating voltage is of great importance for delivering a high-integrating and energy-efficient neuromorphic system. In this paper, we fabricated sub-10 nm ferroelectric capacitors based on HfZrO (HZO) film with varying HfO and ZrO components. Compared to the conventional HZO capacitors (a constant component of 1:1), the varying component ferroelectric capacitors show similar remnant polarization but a lower coercive electric field (Ec). This enables the partial domain switching processed at a lower pulse amplitude and width, which is essential for emulating typical synaptic features. In the MNIST recognition task, the accuracy of sub-10 nm ferroelectric artificial synapse can approach ∼85.83%. Our findings may provide great potential for developing next-generation neuromorphic computing-based ultra-scaled ferroelectric artificial synapses.

Ferroelectricity induced double-direction conductance modulation in HfxZr1-xO2capacitors.

The artificial synapses are basic units in the hardware implementation of neuromorphic computing, whose performances should be gradually modulated under external stimuli. The underlying mechanism of the increasing and decreasing device conductance is still unclear in the Hf0.5Zr0.5O2based synapses. In this study, the Hf0.5Zr0.5O2capacitors with different stack orders are fabricated in atomic layer deposition, whose ferroelectric properties are investigated by analyzing the capacitance-voltage and polarization-voltage curves. The enhanced ferroelectricity is found after the rapid thermal annealing treatment for all the TiN/Hf0.5Zr0.5O2/TiN, TiN/HfO2-ZrO2/TiN and TiN/ZrO2-HfO2/TiN devices. In the device with poor ferroelectricity, the conductance gradually decreases under both positive and negative identical pulse schemes, which corresponds to the gradual dissolution process of the conductive filaments established in the initial pulse. For the capacitors with strong ferroelectricity, dual-direction conductance modulation can be observed due to the partial domain switching process, which can emulate the potentiation and depression process of biological synapses.

A highly CMOS compatible hafnia-based ferroelectric diode.

Memory devices with high speed and high density are highly desired to address the 'memory wall' issue. Here we demonstrated a highly scalable, three-dimensional stackable ferroelectric diode, with its rectifying polarity modulated by the polarization reversal of Hf0.5Zr0.5O2 films. By visualizing the hafnium/zirconium lattice order and oxygen lattice order with atomic-resolution spherical aberration-corrected STEM, we revealed the correlation between the spontaneous polarization of Hf0.5Zr0.5O2 film and the displacement of oxygen atom, thus unambiguously identified the non-centrosymmetric Pca21 orthorhombic phase in Hf0.5Zr0.5O2 film. We further implemented this ferroelectric diode in an 8 layers 3D array. Operation speed as high as 20 ns and robust endurance of more than 109 were demonstrated. The built-in nonlinearity of more than 100 guarantees its self-selective property that eliminates the need for external selectors to suppress the leakage current in large array. This work opens up new opportunities for future memory hierarchy evolution.

Suppression of Filament Overgrowth in Conductive Bridge Random Access Memory by Ta2O5/TaOx Bi-Layer Structure.

Bi-layer structure has been widely adopted to improve the reliability of the conductive bridge random access memory (CBRAM). In this work, we proposed a convenient and economical solution to achieve a Ta2O5/TaOx bi-layer structure by using a low-temperature annealing process. The addition of a TaOx layer acted as an external resistance suppressing the overflow current during set programming, thus achieving the self-compliance switching. As a result, the distributions of high-resistance states and low-resistance states are improved due to the suppression of the overset phenomenon. In addition, the LRS retention of the CBRAM is obviously enhanced due to the recovery of defects in the switching film. This work provides a simple and economical method to improve the reliability of CBRAM.

Present situation and solutions for hospital information platform in China / 医疗卫生装备

Hospital information platform had its present situation and problems in integration introduced, and its construction contents and mode were described. The solutions from some famous foreign companies such as Orion and InterSystems were discussed from the aspects of core architecture and technical characteristics.It's pointed out that urgent requirements and the benefit balance between different companies had to be emphasized so as to develop a platform for data sharing and exchange as well as information export.

CT image retrieval of the liver with intrahepatic lesions / 南方医科大学学报

This paper presents a method for global feature extraction and the application of the boostmetric distance metric method for medical image retrieval. The global feature extraction method used the low frequency subband coefficient of the wavelet decomposition based on the non-tensor product coefficient for piecewise Gaussian fitting. The local features were extracted after semi-automatic segmentation of the lesion areas in the images in the database. The experimental verification of the method using 1688 CT images of the liver containing lesions of liver cancer, liver angioma, and liver cyst confirmed that this feature extraction method improved the detection rate of the lesions with good image retrieval performance.

[Photosynthetic characteristics and dry matter accumulation of hybrid rice varieties under different light conditions].

The study on the photosynthetic characteristics and dry matter accumulation of twelve hybrid rice varieties in the eco-environments with low- and high light intensity showed that the adaptation abiility of the varieties to eco-environment was mainly (depended on the varieties themselves, and there existed greater (differenees among them. The differences in net photosynthetic rate (Pn) and chlorophyll content (Chl) were more significant among the varieties than between the eco-environments. The grain yield had significant positive correlations with Pn and total dry matter mass (TDM), the determination coefficient R2 being 0.584 and 0.590, respectively, but no significant correlations with the export percentage of the matter in stem-sheath (EPMSS) and the transformation percentage of the matter in stem-sheath (TPMSS). In the eco-environment with high light intensity, the leaf thickness and dry matter accumulation increased, while the EPMSS and TPMSS decreased. Under enough sunlight condition, the high proportion of matter in grain yield was mainly come from the photosynthesis at late growth stages; while under insufficient sunlight condition, it was mainly originated from the early growth stages photosynthesis.

A fast 3-D medical image registration algorithm using principal component analysis / 南方医科大学学报

This paper presents a new 3-D image registration method based on the principal component analysis (PCA). Compared with intensity-based registration methods using the whole volume intensity information, our approach utilizes PCA to estimate the centroid and principal axis, and completes the registration by aligning the centroid and principal axis. We evaluated the effectiveness of this approach by applying it to simulated and actual brain image data (MR, CT, PET, and SPECT). The experimental results indicate that the algorithm is effective, especially for registration of 3-D medical images.