It is also possible that the phase-change material experiences a composition change due to etching-induced re-deposition of by-products or thermal stress. 
THERM
It is also possible that the phase-change material experiences a composition change due to etching-induced re-deposition of by-products or thermal stress. 
THERM
It is also possible that the phase-change material experiences a composition change due to etching-induced re-deposition of by-products or thermal stress. 
THERM