Silicon substrate ratio

The fabrication of diodes on silicon substrates was demonstrated using the supramolecular interactions between a 5,10,15,20-tetra(3-fluorophenyl)porphyrin and Ceo fullerene with a rectification ratio of 1,500 (see Fig. 11). The rectifying behavior is explained by theoretical calculations which show that the LUMO orbital is located mainly on the fullerene whereas the HOMO orbital is located on the porphyrin moiety [99]. 

Using this strategy, construction of multilayer films of 0.1 fim thickness by self-assembly of methyl 23-trichlorosilyltricosanoate (MTST) on silicon substrates has been demonstrated (Fig. 9) (165). The linear relationship between the film thickness and the layer number showed a slope of 3.5 nm/layer. EDipsometry data, absorbance intensities, and dichroic ratios for the multilayers all suggest that the samples were composed of distinct monolayers. However, ir data indicated that there maybe more tilting or disordering of the alkyl chains in the seven-layer sample than for the monolayer samples. 

Specific conductive silicon substrates have to be carefully prepared before use. For the diamond-deposition process, substrates have to be cleaned, seeded with diamond nanocrystalline seeds at high surface density, and then coated with a grown thick diamond film (from less than 1 pm up to several p,m) by hot filament chemical vapor deposition (HF-CVD). At Adamant, deposition processes are performed automatically in programmable controlled process units, which allow growing diamond on scale up to 0.5 m2. The process is performed under low pressure (1 < 0.1 bar) and high temperature (filament temperature 2,500°C and substrate temperature 800-1,000°C) with a gas mixture composed of CH4, H2 (CH4/H2 ratio <1%), and a boron source (typically trimethyl boron). 

O and C signals from the substrate by A1 layer is identically constant. These results show that the silicone substrate is simply covered by evaporated Al. By contrast, this O/C ratio increases up to 0.8 for sputtered Al films, which indicates t(je presence of O atoms in the Al films at coverages as high as 25 A and more. These O atoms are coming obviously from the polymer substrate, any contamination from the residual gas can be safely disregarded. 

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