Ge₂Sb₂Te₅ Film Fabrication by Tellurization of Chemical Vapor Deposited GeSb

Abstract

This paper describes stoichiometric Ge2Sb2Te5 (GST) film fabrication by the process based on chemical vapor deposition (CVD). GST films were fabricated by tellurization after GeSb CVD. This two step process enabled to fill high aspect holes. By applying appropriate precursors and process temperature, the surface morphology of the GST film was significantly improved. The moderate tellurization reaction process might contribute GST formation with maintaining the amorphous structure of the CVD GeSb. We believe this technique is useful for phase change memory application.

Growth of Ge Homoepitaxial Films by Metal-Organic Chemical Vapor Deposition Using t-C4H9GeH3

“…This precursor has high vapor pressure appropriate for CVD process, and is expected to be decomposed at low substrate temperature. [20][21][22][23] Furthermore, it is extremely safe without any explosive or pyrophoric natures, and never react with H 2 O. Thus, our selected precursor has much safer than other metal-hydride CVD precursors such as GeH 4 and Ge 2 H 6 .…”

Molecular Precursors for the Phase‐Change Material Germanium‐Antimony‐Telluride, Ge2Sb2Te5 (GST)

“…Several recent publications addressed the metal‐organic chemical vapor deposition (MOCVD) of GST thin films, which will exhibit a good step coverage . 150 nm deep vias of 50 nm diameter could be completely filled with germanium antimony telluride of uniform composition.…”

“…An interesting germanium precursor, which has been employed in some previous studies is liquid tert ‐butylgermane, t BuGeH 3 , . tert ‐Butylgermane was selected as Ge precursor because more conventional Ge tetraalkyl precursors such as Ge R 4 ( R = Et, i Pr, t Bu, allyl) have strong Ge–C bonds; thus, their decomposition temperature may be quite high, and carbon impurities may be incorporated in the resulting GST films.…”

“…The same precursor combination ( t BuGeH 3 / Sb i Pr 3 /Te i Pr 2 ) has also been utilized for a promising way of Ge 2 Sb 2 Te 5 film fabrication by “tellurization” of chemical vapor‐deposited GeSb . This two‐step process made it possible to fill high aspect holes.…”

“…This two‐step process also made it possible to fill high aspect holes. Figure shows a SEM image of a hole with an aspect ratio of 5 after tellurization using Te i Pr 2 . GST thin films could also fabricated by CVD at atmospheric pressure using GeCl 4 , SbCl 5 , and Te precursors in the presence of H 2 as reactive gas.…”