Shadow masking, patterning using

The minimum size of the monochrome pixels (we consider color in Section 13.7.3) that can be fabricated using OLEDs is dictated primarily by the ability to pattern the electrode which is deposited on top. OLEDs are not sufficiently robust to withstand the normal processes of photolithography. Among the schemes which have been suggested for high resolution patterning is one in which the substrate is pne-pattemed to provide its own shadow mask [1911. By this means, pixel sizes down to 300 p have been demonstrated, and a lower limit of about 100 p is estimated. 

Figure 5.9. Functionalization of GaN using the UV-photoinduced reaction with alkenes. Using a shadow mask for the irradiation allows for patterned functionalization. In this study, the alkyl terminated layer was later functionalized with DNA. Figure reproduced with permission from Ref. [152]. Copyright...

Fig. 2.S. Su mmary of some of the shadow masking and surface-treatment results from 3M. A. Photograph of a polymeric aperture mask [30b] used to pattern a wide range of circuits. This mask bears a 6-inch x 6-inch deposition area, with high open aperture ratio. B. Photomicrograph taken of a one-bit RFID circuit patterned using the polymer shadow mask technology [30c], C. Internal clock signal and the externally demodulated rf, or reader signal of the circuit in B (carrier signal was 125...

The source and drain contacts of the examined OFETs were deposited by thermal evaporation of Au as described above for deposition of the radiotracers. Deposition of the contacts was not performed in the same chamber as the radio-tracer deposition in order to avoid contamination of the sample with radioactive isotopes. Patterning of the contact stractures was obtained using a stainless steel shadow mask. By deposition of Au an array of nine contacts was formed. The contact area of the Au was 50 x 50 pm and the distance between the contacts varied from 300 pm to 3290 pm. Three Au contact arrays with a thickness of 50 nm were deposited onto a 40 nm Pc film at a substrate temperature of 75 °C. The first contact array (Array 1 in the following) was deposited at a rate of 0.8 nm/min. For the second set of contacts (Array 2 in the following) first a submonolayer of Au was deposited very slowly (< 1 ML/h) on top of the Pc film in order to allow strong diffusion. Afterwards, the contacts were deposited at the same rate of 0.8 nm/min as the first set. The third array (Array 3 in the following) was deposited at 0.8 nm/min with the substrate at room temperature. 

For the measurements of the ferroelectric hysteresis of P(VDF-TrFE) via the flatband shift, we used capacitors with oxidised p-type (-lO cm ) silicon substrate (100-235 nm Si02) to prevent large amoimts of leakage current. The copolymer film was prepared as described above. We used films of thickness fiom 100 nm to 1 pm. The structiues were prepared in top electrode geometry , with thermal evaporated aluminium, patterned via a shadow mask. The measiuements of capacitance versus voltage (CV) were carried out with an Agilent 4284A LCR meter at a frequency of 1 MHz with sweep rates fiom... 

In response to requirements and manufacturing approaches, different patterning techniques have been developed. Photolithographic techniques similar to those used in Si technology [42, 43] are used. Shadow mask techniques are well... 

A number of other polymer deposition techniques may be used in sensor fabrication. Some of the most exciting are techniques adopted from the semiconductor industry. For example, uncross-linked hydrogel precursors can be cast onto the surface of a substrate and UV cross-linked through a shadow mask. This technique allows patterning of the hydrogel to make complex sensor anays on a single sensor substrate, for example, an integrated O2, CO2, and pH sensor array [23]. 

Fig. 4.13. The process flow presented in [74]. Each layer is patterned using a shadow mask, except for the surface passivation layer which is blanket deposited. The surface passivation layer does not introduce any significant resistance between the gate and source/drain layer. The gate dielectric layer is only deposited where necessary due to the nature of the shadow mask geometry.

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