Analyses of GaN (0001) and surfaces by highly-charged ions

Surface Chemical Analysis Using Multiply Charged Ions

“…Lattice-polarity analysis of GaN(0001) and GaN(0001) surfaces using multicharged ions incident at a grazing an-gle was successful in our previous study [5]. The coincidence detection between a backscattered neutral atom and a secondary ion emitted from the surface leads to SIMS analysis that is very sensitive to the topmost atoms or the adsorbed atoms.…”

“…Faint peaks of substrate atoms such as N + , Ga + , and GaN + were also observed. Desorption or sputtering due to electron capture by multicharged ions is very effective for adsorbed atoms on the surfaces [3,5]. The process is especially effective for proton desorption, since the sputtering proton yield increases in proportion to q 3 ∼ q 5 with an increase in the initial charge state q of the multicharged ion [3,5,10].…”

“…The relative arrival time of a secondary ion was measured with respect to the detection signal of a backscattered ion with a digital oscilloscope [5]. The relative time difference (t) and the 2D-position information (x, y), which was obtained from the pulse heights of three output signals of the wedge-and-strip type 2D-PSD [8], were sequentially recorded using a computer.…”

“…The details of the GaN(0001) surface sample preparation were described in the previ- ous paper [5]. The pressure of the target chamber was kept below 1 × 10 −6 (Pa).…”

“…• with respect to surface normal, which was evaluated from the trajectory simulation using SIMION [3,5,7]. The center axis of the Wien filter was set to 85…”