Integrated Optics - Applied Optics Fundamentals and Device Applications - page 259

8 × 10 13 Ar cm -2

(100) GaAs

100

Annealing of
extended defects

50

Amorphous-to-crystalline
transition (epitaxy)

0 100 200 300 400 500 600

Anneal temperature (°C)

FIGURE 5.24
Normalized disorder, as measured by channeling, for 100 keV 8 × 10 13 Ar cm −2 -implanted (100)
GaAs plotted as a function of furnace annealing temperature (15 min anneals), indicating
two annealing stages. (From Williams, J.S. and Harrison, H.B., In Laser and Electron Beam Solid
Interactions and Material Processing , Gibbons, J.F. et al, eds., North-Holland Publishers, New
York, 1981, p. 209.)

backscattering-channeling spectra, was plotted as a function of the anneal
temperature following an amorphizing implant of 8 × 10 13 Ar cm −2 at 100 keV.
These data revealed two apparent annealing stages, the first occurring rather
sharply in the temperature range 125°C-230°C (for 15 min anneals), followed
by a second stage in the range of 400°C. Channeling cannot unequivocally
reveal the nature of the residual disorder but, from observations of charac-
teristic color changes during annealing, Williams and others [85] suggested
that stage-1 recovery related to defects corresponding to amorphous regions
in the crystal. Kular [86] correlated channeling, TEM, and electrical measure-
ments, and indicated a third anneal stage in which the density of loops was
progressively reduced.
Of further significance are measurements of electrical activity of ion-
implanted GaAs that show continual improvement up to 9000°C [87]. In
view of the anneal process described, the best electrical behavior is at least