Implantation, Diffusion, Activation, and Recrystallization of Gallium Implanted in Preamorphized and Crystalline Germanium

Abstract

We investigated the as-implanted profiles, electrical activation, diffusion, and recrystallization of gallium implanted in germanium samples through the combination of secondary-ion mass spectrometry, transmission electron microscopy, and sheet resistance measurement. Because of their high activation level ͑4.4 ϫ 10 20 cm −3 ͒ without preamorphization, low activation temperature ͑400°C͒, and absence of diffusion ͑up to 700°C͒, Ga junctions in crystalline Ge are very promising candidates for implementation in germanium technology. In the amorphous Ge phase, an increased diffusivity of Ga was observed at temperatures above 400°C.

Direct observation of substitutional Ga after ion implantation in Ge by means of extended x-ray absorption fine structure

“…At low Ga concentrations 2 for the single scattering paths; the R-factor, representing the quality of the fit; best fit E 0 -values and the fraction of substitutional Ga atoms f S .…”

“…However, the low diffusivity and high solid solubility (4:9 Â 10 20 =cm 3 ) of Ga represent a promising alternative p-type dopant. 1 The activation of implanted Ga in Ge has been studied after rapid thermal annealing and flash annealing, 2,3 but so far, the maximum active Ga concentration of 6:6 Â 10 20 =cm 3 has been achieved by Impellizzeri et al after conventional furnace annealing at 450 À 550 C. 4 Higher temperature annealing (! 600 C) resulted in a drastic reduction of the active fraction, attributed to Ga clustering.…”

The formation, stability, and suitability of n-type junctions in germanium formed by solid phase epitaxial recrystallization

“…12,13 A lowtemperature process also reduces the risk of substrate loss and dopant out-gassing, which have been flagged as critical concerns for processing germanium substrates. 14,15 SPER has recently been explored for p-type [16][17][18] and n-type 19,20 dopant activation in germanium but a number of key issues remain. Deactivation kinetics have been studied in silicon [21][22][23] but this aspect is largely unexplored at this point of time for n-type dopants in germanium.…”

Millisecond flash lamp annealing of shallow implanted layers in Ge

“…14 Figures 3͑a͒ and 3͑c͒ depict the sheet resistance of the samples annealed by FLA for 3 and 20 ms, respectively. The flash energy E FLA is given on the abscissa.…”