The annealing characteristics of phosphorous implanted silicon. I

Abstract

Silicon implanted with 3 × 10¹⁴ 20KeV phosphorus ions/cm² was isochronally annealed at temperatures ranging from 600 K to 1250 K. Sheet resistivity measurements of the specimens were taken after each anneal, together with corresponding transmission electron micrographs. The increase in conductivity is explained in terms of a first order thermal reaction with an activation energy of 0.77 eV. The reaction rate for non-crystalline silicon produced by ion beam damage is shown to be about 40 times faster than for crystalline silicon, and occurs at temperatures below 900 K. The recrystallized silicon became epitaxial with the substrate over the temperature range 800 to 1100 K and was accompanied by loss of conductivity by the specimen. This process has been identified as a second order thermal reaction with an activation energy of 1–59 eV. Both reactions are discussed in terms of vacancy mechanisms. A study of the crystal defects in the recrystallized silicon reveals them to be either faulted or prismatic loops of approximately 500 Å diameter.