Amorphous silicon layer characteristics during 70–2000eV Ar+-ion bombardment of Si(100)

Abstract

Spectroscopic ellipsometry ͑SE͒ has been applied to characterize the damaged, amorphous silicon ͑a-Si͒ layer created by Ar + -ion bombardment in the ion energy range of 70-2000 eV impinging at 45°angle of incidence on Si͑100͒. The dielectric functions of a-Si during ion bombardment have been determined using the Tauc-Lorentz model for the dielectric functions ⑀ 1 and ⑀ 2 . The dielectric functions resemble literature reports on a-Si-like dielectric functions. The a-Si layer thickness under ion bombardment conditions reaches values from Ϸ17 Å at 70 eV up to Ϸ95 Å at 2000 eV. These values compare reasonably well with SRIM and molecular dynamics simulations. The surface roughness, as determined with SE, is typically 5 -15 Å during ion bombardment, with a minimum roughness at E ion = 250 eV. The creation of the amorphous silicon top layer upon 70 eV Ar + -ion bombardment with an ion flux of 0.07 ML s −1 has been resolved using real-time spectroscopic ellipsometry. The creation of the amorphous layer shows a double exponential ion-dose dependence: a fast, initial period of a-Si creation, with 1 / e constant ⌬ 1 = 2 ML, and a slower period, ⌬ 2 = 9 ML, until the matrix is fully amorphous after ϳ30 ML of Ar + dosing. Relaxation of the a-Si top layer has been observed after the ions are switched off and has been analyzed with a stretched-exponential decay as a function of time, which is characteristic for a defect-controlled relaxation in the bulk a-Si layer. The corresponding time constant is found to be ϳ360 s, which is typically observed for self-annealing in amorphous silicon materials.

Effects of Ion Beam Irradiation on NanoscaleInOxCooper-Pair Insulators

“…SRIM has been proved to provide results in significant agreement with experiments [19]. Its continuous upgrades during the past decade have made it a foremost tool for numerical analysis of interaction of ions with matter and validation of theoretical predictions [22][23][24]. Transport of ions in matter (TRIM) not only calculates the range of ions in matter, but it also details many other aspects of the damage done to the target during the ion beam slowingdown process, such as cascades of displaced target atoms.…”

Modeling of implantation and mixing damage during etching of SiO2 over Si in fluorocarbon plasmas

“…Defect formation (e.g., vacancies, interstitials, implanted particles) in Si resulting from energetic ion bombardment (1 keV-1 MeV) has been investigated in detail in the context of etching (tens of eV $ 1 keV) and ion-implantation (several to hundreds of keV). [7][8][9][10][11][12][13][14][15][16][17] Characteristics of the amorphous layer produced by ions on Si surfaces have been studied in experiments 10,11 and in molecular dynamics (MD) simulations. [12][13][14][15] The sputtering yield and amorphous layer thickness have been characterized as a function of incident ion energy and angle.…”

Simulated radiation effects in the superinsulating phase of titanium nitride films

“…Sim u la tions were per formed in the TRIM (trans port of ions in mat ter) part of the SRIM soft ware pack age [15], which has been proved to pro vide re sults in signif i cant agree ment with ex per i ments. Its con tin u ous up grades dur ing the past de cade have made it into a fore most tool for nu mer i cal anal y sis of in ter ac tion of ions with mat ter and val i da tion of the o ret i cal pre dictions [16][17][18]. TRIM cal cu lates the range of ions in mat ter, but also de tails many other as pects of the damage done to the tar get dur ing the ion beam slowing-down pro cess, such as cas cades of dis placed tar get at oms.…”