$3)$ Problem $9\mathrm{.}12$

$9\mathrm{.}12.$ a$.$ Using schematic diagrams, show qualitatively how changing the gas pressure in a standard PVD system $($using an appropriate $\backslash ($ S$\_\{$c$\}\backslash )$ value for this type of system$)$ can affect the deposition profile when depositing a material on a narrow trench structure.

b$.$ In a similar fashion, show how changing the sticking coefficient affects the deposition profile when depositing a material on topography with a step.