HOT SPUTTERED ITO - A NEW PROCESS FOR LED
Evatec Product Marketing Manager Franz Xaver Lenherr introduces the new “hot turn table” available on CLUSTERLINE® RAD and the new possibilities it offers to LED manufacturers for ITO deposition.
New opportunities
Although cold ITO deposition processes may be well established, there are always new applications and products in development requiring different material properties.
Changing sputter deposition conditions for materials like ITO could bring other opportunities. Deposition temperature affects the grain shape and the combination of a temperature controlled hot ITO sputter process followed by an annealing process could enable new layer characteristics to be achieved including lower sheet resistance and higher transmission. Heating using traditional front side heating systems extends process times and reduces throughput which is problematic, but that issue can now be avoided with the new “hot turn table” available on CLUSTERLINE® RAD.
Take a look at the results
Figure 1 shows a range of typical hot sputtered films all deposited at the same temperature. Just like for cold processes varying other process conditions allows effective control of grain size.
Figure 2 compares the structures achieved for a cold process with anneal and a hot process without any subsequent anneal. Like always, layer deposition conditions and properties need to be optimised for each manufacturer and device structure and considered in relation to other downstream processes required, but in some cases running a hot process could eliminate the need for a subsequent post deposition anneal.