a wafer level vacuum packaged device having a first substrate having an array of detectors and a second substrate bonded to the first substrate having a plurality of protrusions and a plurality of getter material members projecting outwardly from a sidewall of the protrusions members are disposed at oblique angles to the sidewalls and have ends extending into gaps between the protrusions . the device is formed by : forming protrusions into a surface of a substrate ; and depositing getter material by physical vapor deposition from an evaporating source of the getter material at an oblique angle to the sidewalls , atoms of the getter material initially forming nucleation sites on the sidewalls with subsequent atoms attaching to the nucleation sites and shadowing area surrounding each nucleation site , the getter material thereby growing into structures towards the evaporating source .