Nowadays, researchers are trying to shrink the memory cell in order to increase the capacity of the memory system and reduce the hardware costs. In recent years, there has been a revolution in electronics by using fundamentals of physics to build a new memory for computer application in order to increase the capacity and decrease the power consumption. Increasing the capacity of the memory causes a growth in the chip area. From 1971 to 2012 semiconductor manufacturing process improved from 6µm to 22 µm. In May 2008, S.Williams stated that "it is time to stop shrinking". In his paper, he declared that the process of shrinking memory element has recently become very slow and it is time to use another alternative in order to create memory elements [9]. In this project, we present a new design of a memory array using the new element named Memristor [3]. Memristor is a two-terminal passive electrical element that relates the charge and magnetic flux to each other. The device remained unknown since 1971 when it was discovered by Chua and introduced as the fourth fundamental passive element like capacitor, inductor and resistor [3]. Memristor has a dynamic resistance and it can retain its previous value even after disconnecting the power supply. Due to this interesting behavior of the Memristor, it can be a good replacement for all of the Non-Volatile Memories (NVMs) in the near future. Combination of this newly introduced element with the nanowire crossbar architecture would be a great structure which is called Crossbar Memristor. Some frameworks have recently been introduced in literature that utilized Memristor crossbar array, but there are many challenges to implement the Memristor crossbar array due to fabrication and device limitations. In this work, we proposed a simple design of Memristor crossbar array architecture which uses input feedback in order to preserve its data after each read operation

Au cours des dernières années, la demande de plus en plus forte pour des mémoires non-volatiles performantes, a mené au développement des technologies NOR Flash et NAND Flash, qui dominent aujourd'hui le marché des mémoires non-volatiles. Cependant, la miniaturisation de ces technologies, qui permettait d'en réduire le coût, laisse aujourd'hui entrevoir ses limites. En conséquence, des mémoires alternatives et émergentes sont développées, et parmi celles-ci, la technologie des mémoires à changement de phase, ou PCRAM, est l'une des candidates les plus prometteuses tant pour remplacer les mémoires Flash, notamment de type NOR, que pour accéder à de nouveaux marchés tels que le marché des SCM. Toutefois, afin d'être pleinement compétitives avec les autres technologies mémoires, certaines performances de la technologie PCRAM doivent encore être améliorées. Au cours de cette thèse, nous cherchons donc à obtenir des dispositifs PCRAM plus performants. Parmi les résultats présentés, nous réduisons les courants de programmation et la consommation électrique des dispositifs tout en augmentant la rétention de l'information à haute température. Pour cela, nous modifions la structure du dispositif ou nous utilisons un matériau à changement de phase alternatif. De plus, à l'aide de solutions innovantes, nous permettons aux dispositifs PCRAM de conserver l'information pendant une éventuelle étape de soudure de la puce mémoire. Enfin, nous avons conçu, développé et validé un procédé de fabrication permettant d'intégrer une diode PN de sélection en Silicium en série avec un élément résistif PCRAM, démontrant l'intérêt de ce sélecteur vertical pour être utilisées comme élément de sélection d'une cellule PCRAM intégrée au sein d'une architecture crossbar. / In the past few years, the increasing demand for high quality non-volatile memory (NVM) devices, leads to the developpment of NOR Flash and NAND Flash technologies, which are now the two main NVM players. However, because of some limitations such as performance degradation and limited cost reduction, the scaling of these technologies will reach in the next few years. Therefore, new NVM technologies are under development and among them, phase-change memory (PCM) technology has attracted strong interest and is now became one of the most promising candidates in order to replace Flash technologies, especially NOR Flash technology, and to address new memory markets, such as storage-class-memory market. However, in order to fully take their role in the memory arena, some performances of the PCM technology have to be improved. Therefore, during this PhD, we have tried to improve PCM devices electrical performances by reducing both programming currents and energy consumption while increasing high-temperature data-retention. To this extent, we have studied innovative device structure and alternative phasechange material. Moreover, using innovatives solutions, we show that our PCM devices could store data during the soldering step of the memory chipset. Finally, we have conceived, developed and validated, a process flow in order to make 1D1R PCM cell with Silicon-based vertical PN diodes, proving the relevance of this selector for PCRAM-based crossbar architecture.

Novel devices are being investigated as artificial synapse candidates for neuromorphic computing. These memory devices share the characteristics of an electronic element called memristor. The memristor can be regarded as a resistor with a history dependent resistance, which mimics the plasticity of a biological synapse. The present work presents various types of candidate devices that have been proposed in neuromorphic research, describes how they mimic a biological synapse and how they can be employed in artificial neuron network architectures.

Ces dix dernières années, les technologies de stockage non-volatile Flash ont joué un rôle majeur dans le développement des appareils électroniques mobiles et multimedia (MP3, Smartphone, clés USB, ordinateurs ultraportables…). Afin d’améliorer davantage les performances, augmenter les capacités et diminuer les coûts de fabrication, de nouvelles solutions technologiques sont aujourd’hui étudiées pour pouvoir compléter ou remplacer la technologie Flash. Citées par l’ITRS, les mémoires résistives polymères présentent des caractéristiques très prometteuses : procédés de fabrication à faible coût et possibilité d’intégration haute densité au dessus des niveaux d’interconnexions CMOS ou sur substrat souple. Ce travail de thèse a été consacré au développement et à l'étude des mémoires résistifs organiques à base de polymère de poly-méthyl-méthacrylate (PMMA) et de molécules de fullerènes (C60). Trois axes de recherche ont été menés en parallèle: le développement et la caractérisation physico-chimique de matériaux composites, l’intégration du matériau organique dans des structures de test spécifiques et la caractérisation détaillée du fonctionnement électrique des dispositifs et des performances mémoires. / Over the past decade, non-volatile Flash storage technologies have played a major role in the development of mobile electronics and multimedia (MP3, Smartphone, USB, ultraportable computers ...). To further enhance performances, increase the capacity and reduce manufacturing costs, new technological solutions are now studied to provide complementary solutions or replace Flash technology. Cited by ITRS, the polymer resistive memories present very promising characteristics: low cost processing and ability for integration at high densities above CMOS interconnections or on flexible substrate. This PhD specifically focused on the development and study of composite material made of Poly-Methyl-Methacrylate (PMMA) polymer resist doped with C60 fullerene molecules. Studies were carried out on three different axes in parallel: Composite materials development & characterization, integration of the organic material in specific test structure and advanced devices and finally detailed electrical characterization of memory cells and performances analysis.