Formation of Oxide Layers by High Dose Implantation into Silicon
- PDF / 250,999 Bytes
- 6 Pages / 420.48 x 639 pts Page_size
- 13 Downloads / 229 Views
FORMATION OF OXIDE LAYERS BY HIGH DOSE IMPLANTATION INTO SILICON
S.S. GILL and I. H. WILSON* Royal Signals and Radar Establishment, St Andrews Road, Great Malvern, Worcestershire UR14 3PS, U.K.; *Department of Electronic and Electrical Engineering, University of Surrey, Guildford, Surrey GU2 5XH, U.K.
ABSTRACT Single crystal silicon was implanted with 80, 120, Rutherford backscattering 160 and 240 keV oxygen ions. (RBS) analysis was used to obtain the implanted oxygen profile and the oxygen to silicon ratio in the implanted layer for doses in the range 1016 to 1.5 x 1018 02+ cm-2 The depth and the for room temperature implants. thickness of the buried oxide layer has been measured as a function of implantation energy and oxygen dose. Chemical formation of stoichiometric SiO2 was confirmed Both RBS and IR by infra-red (IR) spectroscopy. indicate that once a surface oxide layer is formed for very high dose levels, the layer thickness decreases with increasing implanted dose beyond a critical dose level.
INTRODUCTION For higher speed, high density VLSI circuits it is desirable to have vertical isolation and low capacitance coupling to the substrate material. At present three choices are available (i) silicon-onand (iii) silicon-onsilicon-on-insulator (SOI)(l) sapphire (SOS) (ii) The limitations of SOS are well known for implanted-oxide SIlOX(2). its high cost, and low mobility of the lattice mismatched top silicon layer. The technique of SO! has been described by Geis et al(l) where Using a moving they used the zone melting recrystallization technique. graphite strip heater they obtained several square cm of single crystal Silicon on insulator has also been silicon on deposited insulator. reported where %. 150 pm long single crystal regions across a whole 3 wafer were obtained using a dual-electron beam system ). Recently Hayafuji et al(4) have reported up to 100 pm wide and 2 cm long quasisingle-crystal Si films on SiO2 obtained using a high-energy density In this paper we shall report results on strip electron beam. synthesizing silicon oxide layers in silicon (both buried and at the surface) by high dose oxygen ion implantation.
METHOD Oxygen ions have been implanted into 4 Qcm p-type silicon at an incident angle of 7o from normal to minimize possibility of The dose range was 1016 to 1.5 x 1018 channeling during implantation. 2 cm- , in most cases molecular oxygen was implanted, with energies per molecule of 80, 120, 160 and 240 keV at nominally room temperature (beam 2 current density 10 pA cm- ). The implanted samples were analysed using Rutherford backscattering (RBS) both in the aligned and non-aligned direction using 1.5 MeV He+ ions. A dual beam Perkin-Elmer spectrophotometer was used to record the IR transmission spectra of the implanted samples.
Mat. Res.Soc.Symp. Proc. Vol. 27 (1984)
Elsevier Science Publishing Co., Inc.
276
RESULTS In figure 1 is shown the peak oxygen to silicon ratio in the implanted layer as a function of oxygen dose for the four implant The oxygen to silicon ratio energies inv
Data Loading...
