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In this article we report the straggling of long-range implantation damage in silicon in the forefront of a focused ion beam induced amorphization zone. Irradiation was carried out at room temperature at a current density of 0.75 A cm−2 (5×1018 ions/cm2 s) using 50 keV Ga+ ions. A highly sensitive tool for detection, an n-metal–oxide–semiconductor field effect transistor is used to quantify and to characterize the distribution profile of ion beam induced electroactive defects. Scanning the beam over active devices allows the extraction of a three-dimensional profile of defects. In situ monitoring of the drive current and intermitting charge pumping measurements revealed the progressive nature of the damage, the generation of interface states, and the lateral extension of irradiation related defects. Far reaching damage cascades extend at least 300 nm in the beam direction and about 220 nm perpendicular to the beam direction of the substrate and define the region of electrically active defects due to parti...

Heterosystems of metal/insulator/gold type with titanium oxide and tantalum oxide as internal barriers are studied using internal photoemission (IPE), field induced current transport (current transients after voltage steps) and chemical reaction induced current transport (chemicurrent). IPE investigations over a broad energy range from 0.8 to 4.5 eV allow a determination of the interstitial layers band gap and the maximum height of the internal tunnel barrier. The built-in field of the heterosystem is derived by the evaluation of the slope in the photoyield versus photon energy plot. Current transients recorded after voltage steps allow the determination of the heterosystems time constants which generally have a value of some milli seconds. In titanium oxide systems additional time constants with values of several 100 s appear for bias voltages >0.5 V. These time constants are assigned to slow processes altering the height of the titanium oxide barriers.

There is an increasing interest in cell-based microelectronic biosensors for high-throughput screening of new products from the biotech pipeline. This requires fundamental knowledge of the biocompatibility of the materials used as the growing support for the cells. Using monolayer-forming Caco-2 cells of human origin, the biocompatibility of silicon wafers coated with various metals, dielectrics and semiconductors was assessed. Besides microscopic inspection, proliferation of cells indicating viability as well as brush border enzyme activity indicating differentiation of adherent growing cells were chosen as parameters to estimate biocompatibility. The type of wafer used for deposition of the coating initially influences the biocompatibility of the final product. Whereas p-doped silicon was fully biocompatible, n-doped silicon reduced the proliferation of cells. Among the different coatings, Al and Ti even increased the cell growth as compared to glass. Culturing the cells for 6 days on coated wafers demonstrated that the differentiation of adhering cells on Ti- and ZrO2-coated wafers was comparable to glass, whereas coatings with Si3N4, Au, Al, and ITO reduced differentiation to 15–35%. In the cases of Au and Si3N4 this effect equilibrated with prolonged culturing. These results demonstrate the importance of a careful selection of the materials used for the production of cell-based biosensors.

For the first time we demonstrate the capability of focused ion beams for engineering in the front end regime. We have shown that by a robust protection for MOSFET, Focused ion beam induced ESD degradation can be avoided and implantation induced damage could be well controlled and mitigated by a moderate RTA process. By a masked through gate implantation technique followed by a moderate annealing/activation process we have exemplarily modified the threshold voltage of test transistors on fully featured wafers whereby any unintentional change of devices nearby could be avoided.

Scanning capacitance microscopy (SCM) is known to be a valuable tool for carrier mapping and profiling on nanoscale semiconductor samples. Certain applications, however, such as quantitative capacitance microscopy on InAs quantum dots, e.g. require low modulation frequencies and complete darkness, which are requirements completely incompatible with the current commercial SCM systems relying on a laser feedback system. For this reason, an intercepted feedback method was developed, which allows to switch off the laser temporarily while the feedback loop keeps running. As an application, images of sub surface InAs self assembled quantum dots were recorded. The InAs dots are clearly visible as bright areas in a contrast-rich capacitance landscape, which we attribute to local thickness variations of the InAs wetting layer in our sample.