Engineering method for tailoring electrical characteristics in TiN/TiOx/HfOx/Au Bi-layer oxide memristive devices

Memristive devices have led to an increased interest in neuromorphic systems. However, different device requirements are needed for the multitude of computation schemes used there. While linear and time-independent conductance modulation is required for machine learning, non-linear and time-dependent properties are necessary for neurobiologically realistic learning schemes. In this context, an adaptation of the resistance switching characteristic is necessary with regard to the desired application. Recently, bi-layer oxide memristive systems have proven to be a suitable device structure for this purpose, as they combine the possibility of a tailored memristive characteristic with low power consumption and uniformity of the device performance. However, this requires technological solutions that allow for precise adjustment of layer thicknesses, defect densities in the oxide layers, and suitable area sizes of the active part of the devices. For this purpose, we have investigated the bi-layer oxide system TiN/TiOx/HfOx/Au with respect to tailored I-V non-linearity, the number of resistance states, electroforming, and operating voltages. Therefore, a 4-inch full device wafer process was used. This process allows a systematic investigation, i.e., the variation of physical device parameters across the wafer as well as a statistical evaluation of the electrical properties with regard to the variability from device to device and from cycle to cycle. For the investigation, the thickness of the HfOx layer was varied between 2 and 8 nm, and the size of the active area of devices was changed between 100 and 2,500 µm2. Furthermore, the influence of the HfOx deposition condition was investigated, which influences the conduction mechanisms from a volume-based, filamentary to an interface-based resistive switching mechanism. Our experimental results are supported by numerical simulations that show the contribution of the HfOx film in the bi-layer memristive system and guide the development of a targeting device

Silicon carbide formation in reactive silicon-carbon multilayers

An alternative low thermal budget silicon carbide syntheses route is presented. The method is based on self-propagating high-temperature synthesis of binary silicon-carbon-based reactive multilayers. With this technique, it is possible to obtain cubic polycrystalline silicon carbide at relatively low annealing temperatures by a solid state reaction. The reaction starts above 600 °C. The transformation process proceeds in a four-step process. The reaction enthalpy was determined to be (-70 ± 4) kJ/mol

An electrothermally actuated Membrane as oscillating Pinhole for the highfrequent Modulation of Light

Differential Confocal Microscopy (DCM) can provide nanometer depth sensitivity for optical profilometry. We investigate a new approach for the creation of a differential depth signal through an oscillating pinhole, thereby reducing overall size, yet enhancing speed of the detection

Mittelfristige Einkommensentwicklung in Sachsen

In Anbetracht rückläufiger Bevölkerungszahlen und einer zugleich alternden Bevölkerung einerseits sowie der vereinbarten Degression des Solidarpaktes II für die neuen Bundesländer ist davon auszugehen, dass die wirtschaftliche Entwicklung im Freistaat Sachsen in den kommenden Jahren eher gedämpft verlaufen wird. Um diese Vermutung quantitativ zu untermauern, wurden in dieser Studie zum einen ökonometrische Projektionsrechnungen zur weiteren wirtschaftlichen Entwicklung in Sachsen vorgenommen. Dabei wurden insbesondere auch die regional unterschiedlichen Ausgangsbedingungen und die daraus resultierenden regionalen Differenzierungen betrachtet; es konnte gezeigt werden, dass insbesondere die eher ländlich geprägten Räume in Sachsen von den zu erwartenden negativen Auswirkungen der demographischen Entwicklung betroffen sein werden, während die Ballungszentren (Dresden und Leipzig, mit Einschränkungen auch Chemnitz) aufgrund ihrer wirtschaftsstrukturellen Besonderheiten und bestehender Agglomerationsvorteile von diesen Einflüssen weitgehend unbeeinflusst bleiben dürften. (Zusammenfassung der Autoren

Identités nationales et conscience européenne

Les contributions et débats de ce volume étudient principalement la genèse et le développement des identités nationales en Europe - principalement en France et en Allemagne - et leur coexistence avec un sentiment d'identité européenne aussi ancien qu'elles, sinon plus.This volume’s contributions and debates study the genesis and development of national identities in Europe and in Germany. It also investigates their coexistence with feelings of European identity as, if not more, ancient than them