Impact of deposition conditions on the crystallization kinetics of amorphous GeTe films
Source abstract
Abstract
The speed at which phase change memory devices can operate depends strongly on the crystallization kinetics of the amorphous phase. To better understand factors that affect the crystallization rate, we have investigated crystallization of GeTe films as a function of their deposition temperatures and deposition rates, using X-ray synchrotron radiation and Raman spectroscopy. As-deposited films were found to be fully amorphous under all conditions, even though films deposited at higher temperatures and lower rates experienced lower effective quench rates. Non-isothermal transformation curves show that the apparent crystallization temperature of GeTe films decreases with increasing deposition temperature and decreasing deposition rate. It was found that this correlates with a decrease in the activation energy for nucleation (calculated using Kissinger’s analysis), while the activation energy for crystal growth remained unaffected. From Raman spectroscopy measurements, it was found that increasing the deposition temperature or decreasing the deposition rate, and therefore the effective quench rate, reduces the number of homopolar Te–Te bonds and thereby reduces the barrier to crystal nucleation.
Source: openaire · Quality: candidate unverified · Source record ↗
Research context
OpenAlex topics: Phase-change materials and chalcogenides · Chalcogenide Semiconductor Thin Films · Liquid Crystal Research Advancements
SciVX discovery tags are terminology-based. OpenAlex topics are source-provided classifications.
References (38)
Show source-provided references
1. Ovshinsky SR (1968) Reversible electrical switching phenomena in disordered structures. Phys Rev Lett 21(20):1450–145310.1103/PhysRevLett.21.1450 ↗
2. Kolobov AV, Fons P, Tominaga J (2007) Phase-change optical recording: past, present, future. Thin Solid Films 515(19):7534–753710.1016/j.tsf.2006.11.183 ↗
3. Wetnic W, Wuttig M (2008) Reversible switching in phase-change materials. Mater Today 11(6):20–27. doi: 10.1016/S1369-7021(08)70118-410.1016/S1369-7021(08)70118-4 ↗
4. Kolobov AV, Fons P, Frenkel AI, Ankudinov AL, Tominaga J, Uruga T (2004) Understanding the phase-change mechanism of rewritable optical media. Nat Mater 3:703–70810.1038/nmat1215 ↗
5. Wuttig M, Yamada N (2007) Phase-change materials for rewriteable data storage. Nat Mater 6:824–83210.1038/nmat2009 ↗
6. Lencer D, Salinga M, Grabowski B, Hickel T, Neugebauer J, Wuttig M (2008) A map for phase-change materials. Nat Mater 7:972–97710.1038/nmat2330 ↗
7. Raoux S, Wenic W, Lelmini D (2010) Phase change materials and their application to nonvolatile memories. Chem Rev 110(1):240–267. doi: 10.1021/cr900040x10.1021/cr900040x ↗
8. Lencer D, Salinga M, Wuttig M (2011) Design rules for phase-change materials in data storage applications. Adv Mater 23(18):2030–2058. doi: 10.1002/adma.20100425510.1002/adma.201004255 ↗
9. Carria E, Mio AM, Gibilisco S, Miritello M, d’Acapito F, Grimaldi MG, Rimini E (2011) Polymorphism of amorphous Ge2Sb2Te5 probed by EXAFS and Raman spectroscopy. Electrochem Solid-State Lett 14(12):480–482. doi: 10.1149/2.019112esl10.1149/2.019112esl ↗
10. Mio AM, Carria E, D’Arrigo G, Gibilisco S, Miritello M, Grimaldi MG, Rimini E (2011) Nucleation and grain growth in as deposited and ion implanted GeTe thin films. J Non-Cryst Solids 357(10):2197–2201. doi: 10.1016/j.jnoncrysol.2011.02.04210.1016/j.jnoncrysol.2011.02.042 ↗
11. Kissinger HE (1957) Reaction kinetics in differential thermal analysis. Anal Chem 29(11):1702–170610.1021/ac60131a045 ↗
12. Tamura N, MacDowell AA, Spolenak R, Valek BC, Bravman JC, Brown WL, Celestre RS, Padmore HA, Batterman BW, Patel JR (2003) Scanning X-ray microdiffraction with submicrometer white beam for strain/stress and orientation mapping in thin films. J Synchrotron Radiat 10:137–143. doi: 10.1107/S090904950202136210.1107/S0909049502021362 ↗
13. Kunz M, Tamura N, Chen K, MacDowell AA, Celestre RS, Church MM, Fakra S, Domning EE, Glossinger JM, Kirschman JL, Morrison GY, Plate DW, Smith BV, Warwick T, Yashchuk VV, Padmore HA, Ustundag E (2009) A dedicated superbend X-ray microdiffraction beamline for materials, geo-, and environmental sciences at the advanced light source. Rev Sci Instrum 80(3):035108. doi: 10.1063/1.309629510.1063/1.3096295 ↗
14. Andrikopoulos KS, Yannopoulos SN, Voyiatzis GA, Kolobov AV, Ribes M, Tominaga J (2006) Raman scattering study of the a-GeTe structure and possible mechanism for the amorphous to crystal transition. J Phys 18(3):965–979. doi: 10.1088/0953-8984/18/3/014
15. Bales GS, Zangwill A (1991) Macroscopic model for columnar growth of amorphous films by sputter deposition. J Vac Sci Technol A 9(1):145–149. doi: 10.1116/1.57711610.1116/1.577116 ↗
16. Tsukimoto S, Moriyama M, Murakami M (2004) Microstructure of amorphous tantalum nitride thin films. Thin Solid Films 460(1–2):222–226. doi: 10.1016/j.tsf.2004.01.07310.1016/j.tsf.2004.01.073 ↗
17. Tamura N (2014) XMAS: a versatile tool for analyzing synchrotron X-ray microdiffraction data, in strain and dislocation gradients from diffraction: spatially-resolved local structure and defects. Imperial College Press, London
18. Matsunaga T, Kojima R, Yamada N, Kifune K, Kubota Y, Tabata Y, Takata M (2006) Single structure widely distributed in a GeTe − Sb2Te3 pseudobinary system: a rock salt structure is retained by intrinsically containing an enormous number of vacancies within its crystal. Inorg Chem 45(5):2235–2241. doi: 10.1021/ic051677w10.1021/ic051677w ↗
19. Ghezzi GE, Morel R, Brenac A, Boudet N, Audier M, Fillot F, Maitrejean S, Hippert F (2012) Crystallization of Ge2Sb2Te5 nanometric phase change material clusters made by gas-phase condensation. Appl Phys Lett 101(23):233113–23311410.1063/1.4769435 ↗
20. Gourvest E, Lhostis S, Kreisel J, Armand M, Maitrejean S, Roule A, Vallee C (2009) Evidence of germanium precipitation in phase-change Ge1-xTex thin films by Raman scattering. Appl Phys Lett 95(3):031908. doi: 10.1063/1.318607710.1063/1.3186077 ↗
21. Carria E, Mio AM, Gibilisco S, Miritello M, Bongiorno C, Grimaldi MG, Rimini E (2012) Amorphous-crystal phase transitions in GexTe1-x alloys. J Electrochem Soc 159(2):H130–H139. doi: 10.1149/2.048202jes10.1149/2.048202jes ↗
22. Friedrich I, Weidenhof V, Njoroge W, Franz P, Wuttig M (2000) Structural transformations of Ge2Sb2Te5 films studied by electrical resistance measurements. J Appl Phys 87(9):4130–413410.1063/1.373041 ↗
23. Choi Y, Jung M, Lee Y-K (2009) Effect of heating rate on the activation energy for crystallization of amorphous Ge2Sb2Te5 thin film. Electrochem Solid-State Lett 12(7):F17–F19. doi: 10.1149/1.312913710.1149/1.3129137 ↗
24. Abu El-Oyoun M (2009) Determination of the crystallization kinetic parameters of Ge22.5Te77.5 glass using model-free and model-fitting methods. J Alloys Compd 486(1–2):1–8. doi: 10.1016/j.jallcom.2009.06.13710.1016/j.jallcom.2009.06.137 ↗
25. Kasyap S, Patel A, Pratap A (2014) Crystallization kinetics of Ti20Zr20Cu60 metallic glass by isoconversional methods using modulated differential scanning calorimetry. J Therm Anal Calorim 116(3):1325–1336. doi: 10.1007/s10973-014-3753-z10.1007/s10973-014-3753-z ↗
26. Dohare C, Mehta N (2012) Iso-conversional kinetic study of non-isothermal crystallization in glassy Se98Ag2 alloy. J Therm Anal Calorim 109(1):247–253. doi: 10.1007/s10973-011-1696-110.1007/s10973-011-1696-1 ↗
27. Wei L, Biao Y, Wen-hai H (2005) Complex primary crystallization kinetics of amorphous Finemet alloy. J Non-Cryst Solids 351(40–42):3320–3324. doi: 10.1016/j.jnoncrysol.2005.08.018
28. Majhi K, Varma KBR (2009) Crystallization kinetic studies of CaBi2B2O7 glasses by non-isothermal methods. J Mater Sci 44:385–391. doi: 10.1007/s10853-008-3149-110.1007/s10853-008-3149-1 ↗
29. Soares RS, Monteiro RCC, Lima MMRA, Sava BA, Elisa M (2014) Phase transformation and microstructural evolution after heat treatment of a terbium-doped lithium-aluminum phosphate glass. J Mater Sci 49:4601–4611. doi: 10.1007/s10853-014-8162-y10.1007/s10853-014-8162-y ↗
30. Lu QM, Libera M (1995) Microstructural measurements of amorphous GeTe crystallization by hot-stage optical microscopy. J Appl Phys 77(2):517–521. doi: 10.1063/1.35903410.1063/1.359034 ↗
31. Chu JP, Lai YW, Lin TN, Wang SF (2000) Deposition and characterization of TiNi-base thin films by sputtering. Mater Sci Eng A A277(1–2):11–17. doi: 10.1016/S0921-5093(99)00560-2
32. Jeyasingh R, Fong SW, Lee J, Li Z, Chang K-W, Mantegazza D, Asheghi M, Goodson KE, Wong HSP (2014) Ultrafast characterization of phase-change material crystallization properties in the melt-quenched amorphous phase. Nano Lett 14(6):3419–3426. doi: 10.1021/nl500940z10.1021/nl500940z ↗
33. Orava J, Hewak DW, Greer AL (2015) Fragile-to-strong crossover in supercooled liquid Ag-In-Sb-Te studied by ultrafast calorimetry. Adv Funct Mater 25(30):4851–4858. doi: 10.1002/adfm.20150160710.1002/adfm.201501607 ↗
34. Andrikopoulos KS, Yannopoulos SN, Kolobov AV, Fons P, Tominaga J (2007) Raman scattering study of GeTe and Ge2Sb2Te5 phase-change materials. J Phys Chem Solids 68(5–6):1074–1078. doi: 10.1016/j.jpcs.2007.02.02710.1016/j.jpcs.2007.02.027 ↗
35. Mazzarello R, Caravati S, Angioletti-Uberti S, Bernasconi M, Parrinello M (2010) Signature of tetrahedral Ge in the Raman spectrum of amorphous phase-change materials. Phys Rev Lett 104(8):08550310.1103/PhysRevLett.104.085503 ↗
36. Pine AS, Dresselhaus G (1971) Raman spectra and lattice dynamics of tellurium. Phys Rev B 4(2):356–37110.1103/PhysRevB.4.356 ↗
37. Fisher G, Tauc J, Verhelle Y (1974) Amorphous and liquid semiconductors. Taylor and Francis, London
38. Hosokawa S, Hari Y, Kouchi T, Ono I, Sato H, Taniguchi M, Hiraya A, Takata Y, Kosugi N, Watanabe M (1998) Electronic structures and local atomic configurations in amorphous GeSe and GeTe. J Phys 10(8):1931–1950. doi: 10.1088/0953-8984/10/8/024