Polymer-assisted deposition of homogeneous metal oxide films to produce nuclear targets.
Targets are essential in experimental nuclear sciences as a source of stationary nuclei for nuclear reactions with ion beams. Typically, targets should be chemically pure, uniform, homogeneous and crack-free over the irradiation area, while also being structurally rigid. The polymer-assisted deposition (PAD) method uses a water-soluble multidentate polymer that chelates metal precursors in solution. This polymer-metal solution is then spin coated and annealed to yield a crack-free, homogeneous metal oxide film. In this protocol, nuclear targets are created using PAD on silicon nitride (Si(3)N(4)) windows with silicon frames. Silicon wafers ([100], single-side polished) coated with 1 microm of silicon nitride on both sides are patterned and etched to create 1-microm silicon nitride windows. The PAD solution is then spun onto the silicon nitride window and annealed to create a thin, uniform metal oxide film of variable thickness on top of the silicon nitride backing. The production of a target window and the deposition of a thin film ranging from 50 to 150 nm takes approximately 13.5 h. Subsequent reapplications to grow thicker films require an additional 5 h per application.
Ali
Mazhar N
MN
Department of Chemistry, University of California, Berkeley, California, USA.
Garcia
Mitch A
MA
Parsons-Moss
T
T
Nitsche
Heino
H
D002621:Chemistry / Q000379:methods; D004601:Elementary Particles; D011108:Polymers / Q000737:chemistry*; D017655:Silicon Compounds / Q000737:chemistry*
D011108:Polymers; D017655:Silicon Compounds; C032734:silicon nitride