A Method of Quantitative Contamination with Metallic Impurities of the Surface of a Silicon Wafer

Abstract

Pancreatic cancer is frequently associated with intense growth of fibrous tissue at the periphery of tumours, but the histopathological quantification of this stromal reaction has not yet been used as a prognostic factor because of the difficulty of obtaining quantitative measures using manual methods. Manual histological grading is a poor indicator of outcome in this type of cancer and there is a clinical need to establish a more sensitive indicator. Recent pancreatic tumour biology research has focused upon the stromal reaction and there is an indication that its histopathological quantification may lead to a new prognostic indicator.Histological samples from 21 cases of pancreatic carcinoma were stained using the sirius red, light-green method. Multiple images from the centre and periphery of each tumour were automatically segmented using colour cluster analysis to subdivide each image into representative colours. These were classified manually as stroma, cell cytoplasm or lumen in order to measure the area of each component in each image. Measured areas were analysed to determine whether the technique could detect spatial differences in the area of each tissue component over all samples, and within individual samples.Over all 21 cases, the area of stromal tissue at the periphery of the tumours exceeded that at the centre by an average of 10.0 percentage points (P < 0.001). Within individual tumours, the algorithm was able to detect significantly more stroma (P < 0.05) at the periphery than the centre in 11 cases, whilst none of the remaining cases had significantly more stromal tissue at the centre than the periphery.The results demonstrate that semi-automated analysis can be used to detect spatial differences in the area of fibrous tissue in routinely stained sections of pancreatic cancer.

First-principles calculations of Cu adsorption on an H-terminated Si surface

“…32 Core electrons are represented by normconserving pseudopotentials using the Troullier-Martins parametrization and including scalar relativistic corrections. The pseudopotential for the silicon atom was generated in the electron configuration ͓Ne͔3s 2 3p 2 , for oxygen in ͓1s 2 ͔2s 2 2p 4 , for copper in ͓Ar͔4s 1 3d 10 , and for hydrogen in 1s 1 , with the square brackets denoting the core electron configurations. After extensive testing of different basis sets, we used double zeta with a single shell of polarization orbitals for Si and H, double zeta with two shells of polarization orbitals for oxygen, and triple zeta with two shells of polarization orbitals for copper.…”

“…Amongst the most common metal impurities, copper has been shown to be much more damaging to electrical properties than, for example, aluminium, iron, or nickel. 1,2 Copper is introduced as a contaminant in several ways, depending on the processing route. Most recently, the adoption of copper as the interconnect material in ultralarge scale integrated devices means that copper can diffuse directly into and through silicon.…”

Light‐induced degradation in copper‐contaminated gallium‐doped silicon

“…1 and 2 were induced through droplets of 1, 5 and 20 ppb% (w/v) copper solution [10]. The higher surface contamination levels were achieved by spin coating the front surface with 8 and 100 ppm% (w/v) of copper solution [11]. The wafers were subsequently annealed for 20 min at 800 °C in a nitrogen atmosphere in order to diffuse the copper contamination into the wafer bulk.…”

Determination of Trace Impurities in Graphite and Silicon Carbide by Total Reflection X-ray Fluorescence Spectrometry after Homogeneous Liquid-Liquid Extraction.

“…[1][2][3][4] When the sample to be analyzed is a solution, it is changed to the solid film on a sample-carrier by the micro-drop method. 5,6) Hence, the preparation of analytical samples and the calibration of observed data are very important in the TXRF analysis of solution samples. If the matrix of a sample solution remains in the solid film, the background and the detector counting-loss possibly increase.…”