Low Phosphorus Concentrations in Si by Diffusion from Doped Oxide Layers

J. Middelhoek, J. Holleman
1974 Journal of the Electrochemical Society  
The diffusion of phosphorus into silicon from doped oxide layers, deposited at low temperatures, has been studied in order to achieve reproducible impurity distributions with surface concentrations varying from 5 • 1015 to 1018 atoms/cm 3. Special attention has been given to the differences arising from indiffusion in an N2 or in an O2 ambient. The dependence on the temperature of the diffusion coefficients of phosphorus in silicon and in silicon dioxide is deter~ mined at a surface
more » ... n of 5 • 1016 atoms/cm 3. ABSTRACT The compositions MnM2m(S,Se)4 where M n ----Eu, Yb, Ca, Sr, Ba and M nI ----A1, Ga, In were prepared by reaction of the elements in evacuated silica tubes with iodine as a mineralizer. All members except Ba(Ga,A1)2S4, which is cubic, exhibit the pseudo-orthorhombic PbGa2Se4 type structure. They are high resistivity p-type semiconductors; they exhibit Eu+a-activated fluorescence which varies from red to blue as the electropositive character of the cations increase. Fluorescence activated by Yb +2 is seen at low temperature. Studies were made of the fluorescence decay lifetimes, temperature dependence, excitation spectra, and optical adsorption of SrGa2S4:Eu in order to relate the Eu+~-activated fluorescence to the host bandgap. It is concluded that the most efficient phosphors are those in which the Eu +2 excited states lie farthest from the fundamental edge. Sulfides and selenides of general formula MnM2 m (S,Se)4 where M n and M nI are divalent and trivalent 1 Deceased. Key words: Eu+~ and yb*2 activated photoluminescence of Mn (A1,Ga,In) 2 (S,Se) 4. cations, respectively, form a variety of structures (1,2). The most common are the Ag2I-IgI4 type, spinel type, ThaP4 type, and CaFe~O4 type. The spinel type is favored by smaller cations while the TI~P4 and CaFe20~ Downloaded 22 Jun 2009 to Redistribution subject to ECS license or copyright; see http://www.ecsdl.org/terms_use.jsp
doi:10.1149/1.2396806 fatcat:msohe5hdkfdenbvfdttwrngu2m