  This paper reviews and extends searches for the direct pair production of the
scalar supersymmetric partners of the top and bottom quarks in proton-proton
collisions collected by the ATLAS collaboration during the LHC Run 1. Most of
the analyses use 20 fb$^{-1}$ of collisions at a centre-of-mass energy of
$\sqrt{s}$ = 8 TeV, although in some case an additional 4.7 fb$^{-1}$ of
collision data at $\sqrt{s}$ = 7 TeV are used. New analyses are introduced to
improve the sensitivity to specific regions of the model parameter space. Since
no evidence of third-generation squarks is found, exclusion limits are derived
by combining several analyses and are presented in both a simplified model
framework, assuming simple decay chains, as well as within the context of more
elaborate phenomenological supersymmetric models.
