ION IMPLANTATION OF SILICON: I. ATOM LOCATION AND LATTICE DISORDER BY MEANS OF 1.0-MeV HELIUM ION SCATTERING

Abstract

The implantation behavior of S b in silicon has been investigated by studying the orientation dependence of the baclcscattering yield of a 1.0-MeV helium bearn. This orientation dependence ("clianneling") provides quantitative information on the location of iinplanted atoms in the lattice and also on the ainount of lattice disorder accompanying the implantation. The general principles of the channeling technique and the advantages of using a beam of I-Ie+ rather than I-I+ are discussed. Results for 25 "C and 450 "C irnplantations are presented and compared. The hot implant introduces very little lattice disorder, and a large fraction (up t o 95%) of the S b atoms is found on substitutional sites. I11 the 25 "C implants, however, a heavily damaged region is formed around the traclc of each iinplanted Sb. At doses greater than -10" ions/cm2, these damaged regions overlap to produce an essentially a m o r p h o~~s layer, which then requires an annealing temperature of -650 "C t o reorder the lattice and to achieve a high level of substitutional Sb. "I-Iot implant" studies have also been made for several other dopants-Ga, As, In, and -Ye; however, unlilce Sb, the substit~~tional level in all these cases never exceeded 60%. This unique behavior of Sb implants in silicon has also been found in a corresponding study of the electrical characteristics (Paper 11). A preliminary investigation of boron-doped silicon, sing the orientation dependence of 610-1ceV protons, indicates that substitutional boron atoms are removed from lattice sites by relatively small doses of energetic protons. This enhanced sensitivity t o radiation does not occur for the Sb-doped samples.

Depth profile and lattice location analysis of Sb atoms in Si/Sb(δ-doped)/Si(001) structures using medium-energy ion scattering spectroscopy

“…This is consistent with reported experimental results on the implantation of Sb atoms into a Si crystal. 8,9 It is proposed that SPE of the Si cap layer and the diffusion of the ␦-doped Sb atoms during the postannealing proceeds in the following steps. Initially, the Sb atoms in the ␦ layer rapidly diffuse into the Si capping layer.…”

Damage profiles of ultrashallow B implants in Si and the Kinchin-Pease relationship

“…However light ion irradiation of low atomic weight materials such as Si, where linear cascade conditions should operate, usually leads to observed production yields well below linear cascade predictions [5][6][7] although for heavier ions values in excess of these have been measured [5][6][7] consistent with expected spike behavior. Such observations have been made with ions of energies in the tens of keV range and above and the former behavior has been ascribed to thermal recombination, or dynamic annealing, of migrating defects.…”

Diffraction and channeling

“…There is no suggestion here, nor was there in I and other papers (Ch.adderton, 1966, Torrens & Chadderton, 1967Torrens, Chadderton & Anderson 1969), that any part of a proper approach in either a well-defined classical or quantum mechanical limit should be replaced by the other. When channeling and its associated phenomena become employed as a tool for solid state research, however, particularly in the study of defects in real crystals (Davies, Denhartog, Eriksson & Mayer, 1967: Picraux, Westmoreland, Mayer, Hart & Marsh, 1969it becomes instructive to examine the transition rrgime in more detail.…”