SOLUTION DERIVED LEAD SOLUTION DERIVED LEAD- FREE (Bi FREE (Bi 0.5 0.5 Na Na 0.5 0.5 )TiO )TiO 3 –BaTiO BaTiO 3 (BNBT) (BNBT) THIN FILMS IN THE PROXIMITY OF THE MORPHOTROPIC PHASE THIN FILMS IN THE PROXIMITY OF THE MORPHOTROPIC PHASE BOUNDARY (MPB) BOUNDARY (MPB) M.D. Mezcua, J. Ricote, D.Chateigner 1 , C. Gutiérrez-Lázaro, I. Bretos, R. Jiménez, R. Sirera 2 and M.L. Calzada M.L. Calzada Instituto Ciencia de Materiales de Madrid, Consejo Superior de Investigaciones Científicas (ICMM-CSIC). Cantoblanco. 28049 – Madrid. Spain. 1 Laboratoire de Cristallographie et Sciences des Matériaux (CRISMAT). Ecole Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN). Université de Caen. 14050 – Caen. France. 2 Departamento de Química y Edafología. Facultad de Ciencias. Universidad de Navarra. 31080 – Pamplona, Navarra. Spain. Instituto de Ciencia Instituto de Ciencia de Materiales de Madrid de Materiales de Madrid
Solution derived lead-free BNBT thin films Solution derived lead-free BNBT thin films 1. Index Instituto de Ciencia Instituto de Ciencia de Materiales de Madrid de Materiales de Madrid
Solution derived lead-free… Solution derived lead-free… 1. Objectives 1. Objectives Instituto de Ciencia Instituto de Ciencia de Materiales de Madrid de Materiales de Madrid
Solution derived lead-free BNBT thin films Solution derived lead-free BNBT thin films 1. Objectives • The main goal of this work is the study of lead-free ferroelectric oxides based on the (1-x)(Bi 0.5 Na 0.5 )TiO 3 -xBaTiO 3 (BNBT) system to replace the well known Pb(Zr x Ti 1-x )O 3 (PZT) and the manufacturing of these materials as thin films for its integration in microelectronic devices. Instituto de Ciencia Instituto de Ciencia de Materiales de Madrid de Materiales de Madrid
Solution derived lead-free BNBT thin films Solution derived lead-free BNBT thin films 1. Objectives Lead-free compositions to substitute lead based- on compositions (PZT) Actual trends on the manufacturing of thin films Integration of ferroelectric Preparation of thin materials in the films information technologies (ITRS 2011) Instituto de Ciencia Instituto de Ciencia de Materiales de Madrid de Materiales de Madrid
Solution derived lead-free BNBT thin films Solution derived lead-free BNBT thin films 2.Introduction 2. Introduction Instituto de Ciencia Instituto de Ciencia de Materiales de Madrid de Materiales de Madrid
2. Introducción Solution derived lead-free… Solution derived lead-free… (1-x)(Bi 0.5 Na 0.5 )TiO 3 -xBaTiO 3 (BNBT) Solid solution BNT-BT Morphotropic phase Phase diagram boundary(MPB) MPB MPB Takenaka et al. Jpn J Appl Phys 1991 ; 30: 2236-39 Thomas et al. Solid State Sci 2008 ; 10:934-940 Instituto de Ciencia Instituto de Ciencia de Materiales de Madrid de Materiales de Madrid
2. Introduction Solution derived lead-free BNBT thin films Solution derived lead-free BNBT thin films Towards the miniaturization of ferroelectric materials and their integration into microelectronic devices ���� ������ ����� ���� ���� ������ ���� ����� ������ ���� ���������� ���� ������ ���� ����� �������� ����� ����� ������� ���� ���� ���� !��� High permitivity Electro-optic activity DRAMs Ferroelectric Pyroelectricity Ferroelectricity films NVFRAMs Piezoelectricity Infrared sensor Sensors Actuators Bretos. Ph. D Thesis UAM 2006 Instituto de Ciencia Instituto de Ciencia de Materiales de Madrid de Materiales de Madrid
Solution derived lead-free… Solution derived lead-free… 2. Introduction Increasing temperature Bulk ceramic Rhombohedral Tetragonal Bi 0.5 Na 0.5 TiO 3 Cubic phase phase phase 528-673K 773-813 K Thomas et al.Solid State Science 2010 ; 12: 311-17 Rhombohedral Rhombohedral Tetragonal Tetragonal Tetragonal Tetragonal Jones et al. Acta Crystallogr B 2000 ; B56:426-30 Jones et al. Acta Crystallogr B 2002 ; B58:168-78 Rhombohedral phase Bi 0.5 Na 0.5 TiO 3 with tetragonal Thomas et al.Solid State Science 2010 ; 12: 311-17 Single-crystal inclusions X-ray diffraction 0.89Bi 0.5 Na 0.5 TiO 3 - Tetragonal 0.11BaTiO 3 Thin film 0.90Bi 0.5 Na 0.5 TiO 3 - Displacement of the The reason Structural effects 0.10BaTiO 3 MPB composition could be Cheng et al. Appl Phys Lett 2004; 85: 2319-21 Bretos et al. Mater Lett 2011 ; 65:2714-2716 Instituto de Ciencia Instituto de Ciencia de Materiales de Madrid de Materiales de Madrid
Solution derived lead-free… Solution derived lead-free… 3. Experimental procedure 3. Experimental Procedure Instituto de Ciencia Instituto de Ciencia de Materiales de Madrid de Materiales de Madrid
Solution derived lead-free BNBT thin films Solution derived lead-free BNBT thin films 3. Experimental procedure Metallic Metallic precursor precursor Metallic precursor Metallic precursor Solvents Solvents Metallic precursor Metallic precursor Solvents Solvents Solvents Solvents Na(OCOCH 3 ).3H 2 O + CH 3 CH 2 COOH + C 4 H 9 OH + CH 3 COOH + Bi(OCOCH 3 ) 3 + Ti(OC 4 H 10 ) BaCO 3 (CH 3 CH 2 CO) 2 O CH 3 COCH 2 COCH 3 OH(CH 2 ) 3 OH + H 2 O Ti(CH 3 COCHCOCH 3 ) 2 (OC 3 H 7 ) 2 Molar ratios 10.0 mol% of Bi(III) excess + Stirring at room 1.0:10.0 f Ti (IV) to Reflux in air for 2 h 10.0 mol% of Na(I) excess temperature any solvents Solvents Solvents Reflux in air for 8h C 4 H 9 OH Stirring at room temperature Bi 0.5 Na 0.5 TiO 3 BaTiO 3 Precursor sol Precursor sol Precursor solution Precursor solution ( � 0.60 mol L -1 ) ( � 0.30 mol L -1 ) Alonso et al. J Am Ceram Soci 2008 ; 92 [10]: 2218-25 Hoffmann el al. J Eur Ceram Soci 1999 : 19 ;1339-1343 Bi 0.5 Na 0.5 TiO 3 -BaTiO 3 Precursor solution ( � 0.60 mol L -1 ) Solvent Solvent C 2 H 5 OH Bi 0.5 Na 0.5 TiO 3 - BaTiO 3 Precursor solution ( � 0.20 mol L -1 ) Instituto de Ciencia Instituto de Ciencia de Materiales de Madrid de Materiales de Madrid
Solution derived lead-free BNBT thin films Solution derived lead-free BNBT thin films 3. Experimental procedure Composition in the vicinity of the MPB Bi 0.5 Na 0.5 TiO 3 BaTiO 3 Bi 0.5 Na 0.5 TiO 3 Precursor sol Precursor solution Precursor sol (BNTs) (BT) ( 10%mol.exc. Bi 2 O 3 +10% mol. exc. NaO) Stirring at room temperature(72 h) BNBTs5.5 BNBT5.5 BNBTs6.5 BNBT10.0 BNBTs8.0 BNBT15.0 BNBTs10.0 BNBTs10.0 Stoichiometric Stoichiometric 10% mol. Bi(III) and Na(I) excesses 10% mol. Bi(III) and Na(I) excesses Dried ethanol Annealed at 900ºC(1h) Diluted solution to Slow Crystalline cooling prepare the films by Heat powders shock CSD Schwartz Cr Chim 2004 ; 7 :433-461 Crystallization: RTP 650ºC/60s 22s 22s 100ºC Refrigeration 25ºC/ 60s 25ºC/ 120s Vacuum Oxygen Instituto de Ciencia Instituto de Ciencia de Materiales de Madrid de Materiales de Madrid
Solution derived lead-free BNBT thin films Solution derived lead-free BNBT thin films 4. Results and discussion 4. Results and discussion Instituto de Ciencia Instituto de Ciencia de Materiales de Madrid de Materiales de Madrid
Solution derived lead-free BNBT thin films Solution derived lead-free BNBT thin films 4. Results and discussion 4.1 Crystalline powders Instituto de Ciencia Instituto de Ciencia de Materiales de Madrid de Materiales de Madrid
Solution derived lead-free BNBT thin films Solution derived lead-free BNBT thin films 4. Results and discussion Structural analysis by XRD of the powders Nominal composition Excesses of Stoichiometric NaO and Bi 2 O 3 For different molar For different molar ratios of BNT/BT Near to Morphotropic phase boundary (MPB) Tetragonal Rhombohedral Coexistence of these structures Takenaka et al. Jpn J Appl Phys 1991 ; 30: 2236-39 Instituto de Ciencia Instituto de Ciencia de Materiales de Madrid de Materiales de Madrid
Solution derived lead-free BNBT thin films Solution derived lead-free BNBT thin films 4. Results and discussion Structural analysis of the crystalline phase in the stoichiometric powders with different BNT/BT molar ratios (200)T a) (021)R b) (003)R Intensity (a.u.) (202)R Intensity (a.u.) (111)T (002)T (101)T (110)T 46.0 46.5 47.0 39.3 39.6 39.9 40.2 40.5 (200)T (002)T 2 θ( º ) 2 θ( º ) 12)T 11)T 11)T Step used 0.005º/5s Step used 0.005º/5s Step used 0.005º/5s Step used 0.005º/5s (111 (2 (001)T )T (100)T )T (0 (11 (21 Intensity (a.u.) (102)T (201)T (210)T BNBTs10.0 JCPDS: * BNBTs8.0 36-0640(Rhombohedral * * * * Bi 0.5 Na 0.5 TiO 3 ) 05-0626(Tetragonal * BNBTs6.5 BaTiO 3 ) * * * * (101)R (012)R (110)R (202)R (113)R (211)R (104)R (003)R (021)R (122)R BNBTs5.5 Step used 0.05º/3s 20 30 40 50 60 2 θ( º ) Jones et al. Acta Crystallogr B 2000 ; B56:426-30 Jones et al. Acta Crystallogr B 2002 ; B58:168-78 Instituto de Ciencia Instituto de Ciencia de Materiales de Madrid de Materiales de Madrid
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