Effect of Selenium Doping on GeSb for Phase Change Memory Applications
In our study, the GeSb film was selected as phase change material due to its fast crystallization speed and selenium was employed doping element for increasing thermal stability and the margin between high and low resistance. When the selenium was incorporated into GeSb film up to 8 at %, the crystallization temperature increased from 150oC to 225oC and the amorphous sheet resistance was elevated more than 13 times compared with undoped GeSb film. In addition, the resistance margin of the film significantly increased more 2 order of magnitude than that of GeSbTe film. The phase separation was found in the GeSb film doped with selenium over 8 at % and this was proved by XRD and XPS analyses. As a consequence, Selenium doped GeSb film was strongly demonstrated as phase change material of PCM cell due to its thermal stability and large resistance margin including high crystallization speed.