文章信息/Info

Title:

Effects of Electron Beam Irradiation on Amorphous GeSbTe Film

作者:

王疆靖; 蔣婷婷; 田琳; 張丹利; 張偉

西安交通大學 金屬材料強度國家重點實驗室 微納尺度材料行為研究中心，陜西 西安 710049

Author(s):

WANG Jiangjing;  JIANG Tingting;  TIAN Lin;  ZHANG Danli;  ZHANG Wei

Center for Advancing Materials Performance from the Nanoscale, State Key Laboratory for Mechanical Behavior of Materials, Xi’an Jiaotong University, Xi’an 710049, China

關鍵詞:

GeSbTe; 非晶; 電子束輻照; 結晶化; 原位TEM

Keywords:

GeSbTe;  amorphous;  electron beam irradiation;  crystallization;  in�瞫itu TEM

DOI:

10.7502/j.issn.1674-3962.2019.02.05

文獻標志碼:

A

摘要:

相變存儲器是目前最具潛力的新式存儲設備之一，其存儲性能主要取決于相變材料的結構�残阅荜P系，因此結構表征對于相變存儲非常重要。透射電子顯微鏡（TEM）是表征材料形貌、結構的重要手段，但是高能電子束會對材料的結構造成暫時或永久性的影響，這種影響也為表征非晶相變材料帶來了極大的挑戰，包括已經商業化的GeSbTe合金。利用原位TEM系統地研究了電子束輻照對GeSb2Te4非晶薄膜樣品的影響，發現非晶薄膜在較大電子束束流強度下會發生結晶化，而降低束流強度將能夠有效保持非晶的穩定性。量化了電子束束流誘發GeSb2Te4非晶薄膜晶化的閾值，給出了電子束流強度和輻照誘導相變時間的關系，為利用TEM研究GeSbTe非晶材料的結構與性能提供了有效的安全界限。

Abstract:

Phase�瞔hange memory is a promising candidate for next generation memory devices. The storage performance greatly depends on the structure�瞤roperty relation of the core material, chalcogenide phase�瞔hange materials (PCMs), which makes the characterization of atomic structure and defects of PCMs crucial to the development of phase�瞔hange memory. Transmission electron microscopy (TEM) is a useful techinque for the characterization of the morphology and structure of materials. However, the high�瞖nergy electron beams can cause temporary or permanent structural changes in materials. These beam effects in fact post challenges in measuring the structural details of amorphous PCMs, including the commercialized GeSbTe compounds. Here, we carried out a systematic in�瞫itu TEM study on amorphous GeSb2Te4 thin films with the focus on electron beam effects. We showed that the amorphous films crystallized quickly if they were subjected to high�瞕ensity electron beams, while by reducing the beam intensity, the amorphous phase can be sustained for longer periods. The threshold values of electron beam intensity under given irradiation time were determined quantitively, and a map displaying the relationship of beam intensity and irradiation time was provided. Our work suggests a safe range for TEM investigations of structural details of amorphous GeSbTe materials.