The resistivity of Ge₁Sb₄Te₇ gradually dropped by about 3–4 orders of magnitude due to crystallization with the annealing temperature, which is critical to realize multiple resistance levels.

The ultra-multiple 27 resistance levels in TiSi₃/GST147 lateral phase-change memory device were demonstrated, much more than reported until now.

The reproducibility of the six resistance levels without programming algorism such as write-certification were demonstrated and these levels were distinguishable from each other.