Specific Process Knowledge/Thin film deposition/Lesker: Difference between revisions
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[[Image:Lesker_roughness_Bjarke.JPG|1000px|thumb|Figure 1:Left: no RF bias (wafer 12) gives high roughness. Right: RF bias (Wafer 21) gives low roughness]] | [[Image:Lesker_roughness_Bjarke.JPG|1000px|thumb|Figure 1:Left: no RF bias (wafer 12) gives high roughness. Right: RF bias (Wafer 21) gives low roughness]] | ||
==Oxide insulation analysis== | |||
The wafers in this analysis consisted of an Si substrate with no native oxide. A layer of SiO2 was reactively sputtered (9% O2 90 W 3.5 mTorr). After that, using a shadow mask, 200nm thick gold rectangles was electrodeposited on top of the oxide. Gold was also electrodeposited on the back side. Then the impedance as function of frequency was recorded. | |||
The figure shows the measurements for different oxide thicknesses. Most of the measurements show perfect capacitors, although for illustration measurements with a few pinholes and a many pinholes is also shown for the 20 nm sample. | |||
The success rate for the different thicknesses can be seen in the table, together with the number of samples measured and the number of perfect capacitors. | |||
It is possible to make perfect capacitors with oxide thicknesses down to and including 5 nm and possibly even thinner, although the failure rate increases. Bear in mind, though that each structure measured here has an area of 8 mm2 - for a 1 mm2 structure the failure rate would be much lower, assuming the short circuits are not located on the sides of the structures. | |||