Engineering Source/Channel/Drain Regions for PMOS TFTs in Flash Lamp Annealed Polycrystalline Silicon

The flat panel industry requires high performance semiconductor materials to withstand the growth rate in the standards of display quality due to the inability of amorphous silicon (a-Si) to support the next generation display manufacturing. Upon research of other materials, low temperature polycrystalline silicon (LTPS) has exhibited the maximum potential considering its high charge carrier mobility. Currently, industry has been employing excimer laser annealing (ELA) process for production of polycrystalline silicon from amorphous silicon which is an expensive process and limits its usability to small screen displays. Flash lamp annealing (FLA) is another approach that is cost efficient and can be utilized for large glass panels and presents itself as a potential candidate to replace ELA; however challenges in obtaining uniform morphology over large areas must be addressed. Previous work on FLA polycrystalline silicon TFTs demonstrated high carrier mobility but exhibited scalability issues due to liquid-phase dopant diffusion. To avoid this issue, dopants were ion implanted post-FLA, then activated through furnace annealing at relatively low temperatures (T ≤ 700 °C). This procedure resulted in reasonable dopant activation, and p-channel TFT operating characteristics with an effective hole channel mobility of 40 – 50 cm2/(Vs). However 700 °C annealing was required to promote TFT electrical performance, which is beyond a practical limit for large panel manufacturing. This work presents on strategies which use FLA for both crystallization and dopant activation processes. An initial study explored low intensity FLA for partial solid-phase crystallization of a-Si to realize microcrystalline material with mixed-phase morphology, with crystallization and dopant activation processes occurring simultaneously. Exceedingly high series resistance rendered the material incapable of demonstrating working TFTs. Efforts were then redirected based on the success of an approach using pre-amorphization of FLA LTPS by Si+ ion implantation, followed by boron ion implantation and activation through solid-phase crystallization in the source/drain regions. The pre-amorphization process demonstrated improved TFT characteristics on both furnace anneal treatments done at lower temperature (T = 630 °C) and FLA activation treatments. This approach was modified to include a furnace anneal treatment in between the Si+ pre-amorphization and boron ion implant processes, which following FLA activation has yielded the lowest sheet resistance obtained thus far (Rs \u3c 400 Ω/□). This high level of boron activation suggests the lack of extended defects, and thus the potential to realize an improvement in transitions at the source/channel and channel/drain interface regions

DeformNet: Free-Form Deformation Network for 3D Shape Reconstruction from a Single Image

3D reconstruction from a single image is a key problem in multiple applications ranging from robotic manipulation to augmented reality. Prior methods have tackled this problem through generative models which predict 3D reconstructions as voxels or point clouds. However, these methods can be computationally expensive and miss fine details. We introduce a new differentiable layer for 3D data deformation and use it in DeformNet to learn a model for 3D reconstruction-through-deformation. DeformNet takes an image input, searches the nearest shape template from a database, and deforms the template to match the query image. We evaluate our approach on the ShapeNet dataset and show that - (a) the Free-Form Deformation layer is a powerful new building block for Deep Learning models that manipulate 3D data (b) DeformNet uses this FFD layer combined with shape retrieval for smooth and detail-preserving 3D reconstruction of qualitatively plausible point clouds with respect to a single query image (c) compared to other state-of-the-art 3D reconstruction methods, DeformNet quantitatively matches or outperforms their benchmarks by significant margins. For more information, visit: https://deformnet-site.github.io/DeformNet-website/ .Comment: 11 pages, 9 figures, NIP

Flash lamp annealed polycrystalline silicon as a potential candidate for large panel manufacturing

The flat-panel display industry is in pursuit of TFT manufacturing processes which are cost-effective, easily scalable to large glass panels, and meet the performance requirements of advanced display products. While excimer laser anneal (ELA) low-temperature polycrystalline silicon (LTPS) can offer exceptional TFT performance, a lower grade LTPS may still satisfy product requirements at a lower production cost. Flash-Lamp Annealing (FLA) is an emerging candidate for the manufacture of LTPS. Multi-lamp exposure systems with high repetition pulse rates would potentially offer significant advantages in manufacturing throughput and cost over ELA. Techniques to overcome challenges that have hindered device scaling and reduction in variation of device operation are under investigation. The following presents a status update on the development of FLA Polycrystalline Silicon (FLAPS) technology. The FLA equipment used for this work was a NovaCentrix PulseForge 3300 system, capable of uniform exposure of a 7 cm x 12 cm area at intensities as high as 50 kW/cm2 over microseconds pulse duration. PMOS TFTs were fabricated using combinations of FLA, ion implantation and furnace annealing to define the source/drain and channel regions. Predefined polygons of 60 nm thick amorphous silicon vertically sandwiched between layers of SiO2 were crystallized on Corning Lotus NXT display glass using single-pulse FLA exposure. The amorphous silicon melts while absorbing a sufficient fraction of the xenon emission spectrum, and becomes polycrystalline while staying within the thermal constraints of the underlying glass substrate. Boron dopant ions were implantation into the source/drain regions defined by lithographic patterning or a self-aligned gate strategy. Boron activation was realized by combinations of FLA, furnace annealing, and pre-amorphization using an electrically inactive species. FLA conditions following dopant introduction avoided silicon melting which causes significant lateral diffusion. Representative electrical characteristics are shown in figure 1. While the device operation demonstrates a general dependence on the degree of dopant activation, observations on the electrical characteristics indicate a complex relationship between defect states and the specific implant/activation strategy applied. The influence of doping strategy on both device performance and resistance to failure is the primary focus of this work. Additional experiments involving variations in the FLAPS morphology will also be discussed. Please click Additional Files below to see the full abstract

Shape memory textiles for smart compression management for chronic venous disorders – A review

In conventional compression treatment using bandage or stocking, always there has been a problem of achieving and maintaining the recommended compression gradient and level. In addition, these devices are incapable of offering dynamic (massaging) compression, often preferred especially for senior and non-active patients to improve blood flow. To overcome these challenges, the application of shape memory materials is proven to provide a dynamic or selective pressure change directly on the limb. Memory material-based stockings or bandage have the potential to tackle the drawbacks of existing stockings by allowing users to modify pressure levels externally as needed during compression therapy, i.e. as a smart wound care device. This paper reports the consolidated information on traditional compression systems, their challenges, and modern methods involving active compression bandages based on smart materials technology (via shape memory polymer or shape memory alloy), which develop intermittent active pressure to alleviate the symptoms of lower limb problems

Shape memory textiles for smart compression management for chronic venous disorders – A review

131-145In conventional compression treatment using bandage or stocking, always there has been a problem of achieving and maintaining the recommended compression gradient and level. In addition, these devices are incapable of offering dynamic (massaging) compression, often preferred especially for senior and non-active patients to improve blood flow. To overcome these challenges, the application of shape memory materials is proven to provide a dynamic or selective pressure change directly on the limb. Memory material-based stockings or bandage have the potential to tackle the drawbacks of existing stockings by allowing users to modify pressure levels externally as needed during compression therapy, i.e. as a smart wound care device. This paper reports the consolidated information on traditional compression systems, their challenges, and modern methods involving active compression bandages based on smart materials technology (via shape memory polymer or shape memory alloy), which develop intermittent active pressure to alleviate the symptoms of lower limb problems