Selective emitters in Si by single step rapid thermal diffusion forphotovoltaic devices

Selective phosphorous diffusion is performed in Si to simultaneously form shallow n⁺p junctions of different depths in the submicron range by rapid thermal annealing (RTA). Low temperature (400°C) atmospheric pressure chemical vapor deposited (APCVD) phosphosilicate glass (PSG) is used as diffusion source. A wide range of n⁺p junctions could be tailored with the same thermal budget by changing only the APCVD-PSG composition. This allows the formation of selectively diffused emitters in different regions of the wafer in one RTA step. 10 cm×10 cm Cz-Si selective emitter photovoltaic (PV) devices are fabricated this way with high energy conversion efficiencies in the range of 17% to 18%     

Surface recombination current with a nonideality factor greaterthan 2

It is shown both theoretically and experimentally that under inverted surface conditions the surface recombination current of a bipolar transistor has an exponential nonideality factor >2. The behavior of the surface recombination current follows closely that of the excess leakage current in stressed-self-aligned silicon bipolar transistors at forward bias     

IV. Referate

Ohne Zusammenfassung     

Design and analysis of a state observer for the temperature front of a retification column

In order to achieve optimal energy-saving, load-dependent operation of rectification columns, development and implementation of model-based control concepts are necessary. This paper reports on the design and step-by-step testing of a state observer for the estimation of two state variables which cannot be measured directly, namely the vapour rate and the location of mass transfer zone (temperature front) in the stripping section of a production column. The procedure is described, and the relevant simulation and operation results are presented and discussed. Initial experience, gained when the concept was put into practical operation, is reported.     

Vorwort der Herausgeber

Ohne Zusammenfassung     

Verbindung von wissensbasierten Systemen mit Simulation im Fertigungsbereich

Zusammenfassung Wissensbasierte Systeme können helfen, die Simulation für eine breitere Anwenderschicht nutzbar zu machen. Dazu werden Klassifikationen nach der Architektur und nach der Aufgabenteilung vorgestellt. Letztere unterscheidet Programme zur automatischen Generierung von Modellen, Systeme, die den Benutzer bei der Interaktion unterstützen, und Expertensysteme, die Simulation zur Wissensakquisition nutzen. Als Beispiele werden Simulation Craft und ein System vorgestellt, das durch Koppelung von Expertensystemen, Simulation und einem PPS-System die Umdisposition in der Fertigungsplanung unterstützen soll.

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Summary Knowledge based systems can be helpful to give a wider group of users access to simulation. Classifications are given for systems according to their structure and their task-sharing approach. Among the latter are systems that enable automated model creation, support the interaction of user and expert system and others, that utilize simulation as a means of knowledge acquisition. Two examples are given: Simulation Craft and a system that will support rescheduling in production environments by combining expert systems, simulation and manufacturing systems.