Silicon oxide deposition, surface imaging

Figure 7.16 Left Spreading of a drop of PDMS on a silicon wafer observed with an ellipsometer 19 h after deposition. Redrawn after Ref. [283], On a much smaller scale (right) prewetting layers around droplets of polystyrene on a flat silicon oxide surface are observed. The atomic force microscope image shows an area of (2.5 /um)2 [284].

Laser ablation was used [22] to produce SiNWs 20 nm in diameter with a polycrystalline silicon core in a thin silicon oxide sheath with 1/4-1/3 of the nominal diameter and 1/3 of the weight of the SiNW. The oxide layer (which makes the SiNWs surfaces inert) was removed by a 5% H F dip for 5 min resulting in smooth, stable, H-terminated SiNW surfaces [77]. The etched SiNWs were immersed into solutions of silver nitrate and copper sulfate of different concentrations. Silver and copper ions were reduced to metallic aggregates deposited onto the surface of SiNWs. The TEM image of the sample treated with a 10 M silver nitrate solution (Figure 10.28) shows dark, round silver particles 5-50 nm in diameter. The HF-etched SiNWs treated with 1.0 x 10 M copper sulfate show much smaller (a few nm) particles (Figure 10.29) identified by EELS as Cu particles. 

Figure 1 shows the surface imaging system using photogenerated add-catalyzed SiOj formation by the chemical vapor deposition (CVD) method. Upon irradiation with UV light the surface of polymers having imino sulfonate units becomes hydrophilic because of the formation of sulfonic add. Water sorption firom the atmosphere occurs at the top surface of the irradiated films. When the irradiated surface is exposed to the vapor of alkoxysUanes, a silicon oxide network is formed at the near surface of Ae polymers. No silicon oxide network is formed at unirradiated areas... 

Besides using the resists to etch copper boards, metal parts, or silicon surfaces, new applications have been disclosed. Spatial images have been holographically recorded in resists.— The resist systems of siloxanes can be converted after imaging by oxidation into passivated glass for direct formation of insulated circuits.— The resist can be filled with glass 9 or metals— and fired to form circuits directly. In one application, the resists are filled with electroless plating sensitizer for deposition of... 

---