碲化鍺添加銻/鉍/銦相變化記錄材料研究

Study of Sb-Bi-In Doped GeTe Phase Change Recording Materials

吳重慶(Chong-Qing Wu)

指導教授 ： 陳貞光 ； 洪胤庭

國立臺北科技大學/工程學院/材料科學與工程研究所/碩士(2009年)

https://doi.org/10.6841/NTUT.2009.00519

摘要

硫屬化合物已大量應用在紅光與藍光光碟的重複讀寫式記錄媒體中，當低熔點元素與高熔點金屬元素混合進行合金製作時，通常具有較低的沸點與較高的蒸氣壓，因此傾向造成低熔點元素成分的流失與污染。
第一部分的研究為使用高真空電爐熔煉與真空感應熔煉製程，在GeTe二元合金中添加適量的低熔點元素（Bi和In）取代部分Ge，探討兩種熔煉製程，對於合金成分分析、結晶構造、顯微組織以及熱性質之影響。研究結果顯示利用高真空感應熔煉製程對於高熔點元素(Ge)的熔煉效果較為完整，而真空電爐熔煉製程，則顯示控制不穩定的情形。合金鑄錠的結構分析結果為FCC結構的GeTe基地相，以及菱方晶結構的Ge3Bi2Te6相。
第二部份的研究為利用直流濺鍍製備(Ge40Te52)1-n(SbxBiyInz)n, (n=0.08)薄膜，並探討添加Sb、Bi、In對於相變化記錄薄膜的微結構、熱性質、光學性質的影響。經由X-ray繞射分析結果得知，結晶薄膜出現GeTe相和GeTe4相；熱性質分析結果得知，添加Sb將促進GeTe4介穩定相形成，且GeTe4相形成有助於降低結晶活化能。Sb原子被Te原子取代有助於降低結晶溫度；(Ge40Te52)1-n(BiIn)n=0.08薄膜結晶相與非晶相之間的反射率對比高達20.2%以上；(Ge40Te52)1-n(SbBiIn)n=0.08薄膜則有37.2%以上的表現。

關鍵字

硫屬化合物 ； 低熔點高蒸氣壓元素 ； 真空感應熔煉 ； 相變化材料

並列摘要

Chalcogenide compounds are often utilized as recording materials in rewritable optical discs. The chalcogenide elements with low melting points tend to lose more during melting due to their high vapor pressures. In the first part of the study, low melting point elements of antimony (Sb), bismuth (Bi) and indium (In) are added to a germanium-tellurium (GeTe) binary alloy in substitution for Ge. Two different processes are applied: vacuum melting and vacuum induction melting. Their compositions, crystal structures, microstructures, and thermal properties are analyzed. It is shown that better composition uniformity is achieved by vacuum induction melting process. Two phases are observed in the as-cast alloy to be fcc GeTe and rhombohedral Ge3Bi2Te6 phases. Both Sb and Bi lower the melting points of the designed alloys according to the thermal analysis.
In the second part of the study, thin films of (Ge40Te52)1-n(SbxBiyInz)n, (n=0.08) are deposited by DC sputtering system. The effects of Sb/Bi/In on the microstructure, thermal properties, and optical properties of the phase-change record thin film are discussed. These films are shown to contain mixtures of GeTe and GeTe4 phases. Sb assists in stabilizing the metastable GeTe4 phase and decreases the activation energy for crystallization. The reflectivity contrast between amorphous and crystalline state reaches values above 20.2% for the (Ge40Te52)1-n(BiIn)n=0.08 film and above 37.2% for the (Ge40Te52)1-n(SbBiIn)n=0.08 film.

並列關鍵字

chalcogenide compounds ； high vapor pressure ； vacuum induction melting ； phase change materials

參考文獻

[3]S. R. Ovshinsky, “Reversible Electrical Switching Phenomena in Disordered Structures,” Physical Review Letters, vol. 21, no. 20, 1968, pp. 1450-1453.

[5]M. Shinotsuka, T. Shibaguchi, M. abe and Y. Ide, “Potentiality of the Ag-In-Sb-Te phase change recording material for high density erasable optical discs,” Jpn. J. Appl. Phys. vol. 36, 1997, pp. 536-538.

[6]K. Kim and G. Jeong, Microsyst. Technol, vol. 13, 2007, pp. 145-147.

[9]S. Ohkubo, T. Ide, and M. Okada, Technical Digest of Optical Data Storage Topical Meeting, New Mexico, 2001, pp. 34.

[10]K. Schwartz, The Physics of Optical Recording, Springer-Verlag, Berlin Heidelberg, 1993, pp. 150.