Correlation between crystallization behavior, electrical switching and local atomic structure of Ge–Te glasses

Experimental evidence for presence of voids in phase change memory material

“…First, it is evident from the Raman spectroscopic and SAED pattern on Ge 20 Te 80 glass and crystalline sample, respectively, that there is not much change in the local atomic structure despite its better performance in phase change property. 39 This emphasizes that the origin of defect size and/or density between the two phases plays a crucial role in the phase change behaviour, more than the presence/absence of resonance bonding and change in coordination numbers as seen by earlier studies. 5,6,52 Secondly, we ascribe the large concentration of defects at the low germanium content level to unusually high electronic polarizability of the network structure by the presence of lone pairs of electrons at the tellurium atoms.…”

“…It has been observed that Ge x Te 100Àx glasses with x ¼ 20 (dened as critical composition, x c ) show distinct behaviour in various physical properties such as thermal diffusivity, electrical resistivity, crystallization (disappearance of two stage), electrical switching voltage etc. [36][37][38][39] In the present work, the critical composition has been characterized by equal amounts of CS and ES tetrahedral units in glass/crystal and gives rise to the onset of a rigid network structure. The CS tetrahedral unit of all Ge-Te bonds connects the backbone of the network against the only two bonds in the ES tetrahedral unit.…”

Nonideal Behavior of Glass and Crystal

“…The obtained density value on Ge 20 Te 80 glass composition (G3) is close to those reported in the literature. 26 More Interestingly, we find systematic change in density in all the four crystalline specimens which is even more unusual than the glass behavior. Again, the density variation in crystalline sample with different thermal history of respective glass sample indicates the stable equilibrium configuration depends on the materials previous thermal history.…”

Temperature‐Dependent Local Structural Changes of Amorphous Thin Ge20Te80 Film Revealed by In Situ Resistance, X‐Ray Diffraction, and Raman Spectroscopy Studies

“…This systematic exploration of Ge 20 Te 80 thin film demonstrates the thermally stable vitreous phase ensured up to 180 °C and the single transition around 238 °C corresponding to single T c of Ge 20 Te 80 film. [ 10,29 ] Hence, Ge 20 Te 80 confirms better thermal stability compared with Ge 15 Te 85 thereby enabling improved thermal and structural properties that are important for stable OTS selector performances.…”