Focused-ion-beam implantation of Ga in elemental and compound semiconductors

Abstract

Small-area ͓ϳ͑50 m͒ 2 ͔, focused-ion-beam implantation of 25 keV Ga ϩ in Si, Ge, InP, InSb, and ZnSe was investigated by experiments and by computer simulations. Specifically, the Ga concentration was determined for implantation fluences ⌽ ranging from 1ϫ10 14 to 3ϫ10 17 Ga ϩ ions/cm 2 by means of secondary-ion mass spectrometry. In all materials the Ga peak concentration exhibits an essentially linear increase with fluence up to some 10 16 cm Ϫ2 ; for higher values of ⌽ the Ga concentration tends to saturate. The saturation content of Ga at the surface c ϱ ranges from ϳ2 at % for ZnSe to ϳ40 at % for Si. These values appear roughly inversely correlated with the specimens' sputtering yields and agree thus with the predictions of a model of ion retention in the presence of concurrent sputter erosion. The computer simulations with the dynamic binary-collision-approximation code T-DYN produce a fluence-dependent evolution of the Ga concentrations in the examined semiconductors which is in qualitative agreement with the experiments. Furthermore, partial sputtering yields and the most probable ranges for 25 keV Ga ϩ impact on the different materials have been determined both experimentally and from the simulation output.

Focused ion beam implantation of Ga in nanocrystalline diamond: Fluence-dependent retention and sputtering

“…Experiments to determine the high-fluence concentration due to metal ion implantation at beam energies which are typical for SIMS and FIB (some 10 keV) have been carried out primarily for Si [18][19][20][21][22][23]. However, only a rather limited fluence range was studied.…”

Crystallinity-retaining removal of germanium by direct-write focused electron beam induced etching

“…Gnaser et al reported a gallium concentration of up to 21% by secondary-ion mass spectrometry ͑SIMS͒ after FIB exposure of a Ge surface. 8 This leads to a dramatic change of the electrical properties of a germanium sample, 11 in effect rendering FIB-mediated material removal useless for many applications. In order to overcome these disadvantages it is desirable to use electrons instead of ions because an etching process involving only electrons will remove material solely chemically.…”

“…Material removal in the nanometer scale by physical sputtering using the focused ion beam ͑FIB͒ technique is well established but exhibits significant gallium implantation 8,9 into the substrate and amorphization of the substrate 10 as undesirable side-effects. Gnaser et al reported a gallium concentration of up to 21% by secondary-ion mass spectrometry ͑SIMS͒ after FIB exposure of a Ge surface.…”

SIMS investigation of CrN sputtercoatings

“…These efforts have to be put up with since nitrogen is the interesting element in this investigation. With the use of CsN + the matrix dependency of the signal can be suppressed and the real concentration of the measured component can be estimated more exactly [5]. Therefore, CsN + has to be evaluated for these studies.…”