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Metal–insulator–semiconductor structures with a layer of silicon nanocrystals embedded within the SiO2 layer at a tunneling distance from a p-type silicon substrate and fabricated using chemical vapor deposition, oxidation, and annealing, exhibited charge trapping, determined from the capacitance–voltage (C–V) characteristics, which abruptly increased at fields above 2.5 MV/cm. Electrons or holes are trapped when biasing the structure into inversion or accumulation, respectively, and retention of trapped charge is demonstrated. The I–V characteristics exhibit an N-shaped form, indicating screening effects due to charging; an initial current spike, attributed to transient charging of nanocrystals, occurs at the same voltage causing abrupt C–V shift increase, with Fowler–Nordheim current rising at higher voltages. These structures are promising for memory device applications.

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This work presents the characterization of a thermal vacuum sensor, directly integrated on a printed circuit board (PCB) substrate. The sensor consists of a thin platinum strip, in direct electrical contact with the patterned Cu tracks of the PCB. The platinum resistor that resides on a thick SU‐8 layer on the PCB, acts as both heating and temperature sensing element. Both PCB substrate and SU‐8 have low thermal conductivity values, therefore ensuring a high degree of thermal isolation. Under electrical current flow through the Pt heater, an elevated temperature field is developed in its vicinity due to Joule heating. The overall heat exchange rate is a function of the surrounding gas pressure in certain pressure regimes due to the contribution of different heat transfer mechanisms. The determination of heat transfer allows for the extraction of the corresponding vacuum value. The sensor operation was tested in a pressure range from 103 to 10–5 mbar for three different operation modes, namely that of constant current (CI), constant temperature (CT) and constant power (CP). (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)