Structural, electric and kinetic parameters of ternary alloys of GeSbTe

Crystallization of Ge:Sb:Te Thin Films for Phase Change Memory Application

“…It is well known from the literature that deposition technology strongly affects the microstructure and as a results the optical, electrical and crystallization (especially the crystallization temperature) properties of phase-change materials. For example, the crystallization temperature of the films with the same composition but obtained by different deposition methods can differ for more than 20 0 C, and no suitable explanation has yet been proposed (Morales-Sanchez et al, 2005). That is why, to compare crystallization properties all studied films have to be obtained with the same deposition process (DC sputtering), with the same thickness (around 200 nm), and composition along the GeTe-Sb 2 Te 3 pseudobinary line.…”

“…This alloy crystallizes in NaCl-type structure (Gonzalez-Hernandez et al, 1992, Wamwangi et al, 2002, Ruiz Santos et al, 2010. For Ge 4 Sb 1 Te 5 films the reported values of the activation energy varied in a wide range: 1.13 eV (Kato et al, 1999), 3.09 eV (Morales-Sanchez et al, 2005), 3.48 eV (Wamwangi et al, 2002).…”

“…It is suggested (Coombs et al, 1995) that this alloy is a solid solution between GeTe and a compound with a composition close to Ge 4 Sb 1 Te 5 . This material, in contrast to stoichiometric alloys, demonstrates only one amorphous-NaCl-type phase transition, but it has the largest optical (Kato et al, 1999) and electrical (Morales-Sanchez et al, 2005) contrast between the crystalline and amorphous states, compared with other Ge:Sb:Te ternary alloys.…”

A slope-theory approach to electrical probe recording on phase-change media

“…The small heat rate limit corresponds to ramped annealing measurements that are used to characterize phase-change media ͑for example, resistance measurements, 6,29 and differential scanning calorimetry 14 ͒, while the high heating rate regime simulates the situation of laser recording in optical storage.…”

“…13,17 It also explains why the use of the Kissinger method for determining the kinetic parameters of crystallization in phase-change media is appropriate in thermal annealing experiments adopted by many workers. 6,15,16,29 The transition temperature is identified as the temperature of maximum crystallization rate 12 at which ‫ץ‬ 2 / ‫ץ‬t 2 =0. Thus, differentiating ͑21͒ with respect to time and assuming that A does not change significantly near the maximum, 13 leads to the following condition at the transition temperature:…”