Effect of Post Metallization Annealing for La 2 O 3 Thin Film

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Annealing temperature from 200 o C to 450 o C was investigated withregard to aluminum upper electrodes, from 300 o C to 450 o C was investigatedwith regard to gold upper electrodes and from 300 o C to 600 o C wasinvestigated in regard with platinum upper electrodes respectively.These fabricated MIS capacitors were characterized by C-V and J-V.MetalPDAPMAn-Si(100)Si Resistivity:0.02 - 0.8[Ω・m]Thickness:3~6 [nm]La 2 O 3 DepositionAt 250 o CLa 2 O 3Temperature:200 o C~450 o CTime:Spike~100 minutesLa 2 O 3Ambience:N 2 , O 2 or F/GMetal Material:•Aluminum•Gold•PlatinumTemperature:200 o C~600 o CTime:Spike~100 minutesAmbience:N 2 , O 2 or F/GMetalAlWet CleaningandSurface Treatment•HF-last•Chemical OxidationRare Earth Deposition(MBE)•PDAAnnealing Process (RTA)•PMAUpper Metal Evaporation•PDAUpper Metal EvaporationPMAAnnealing Process (RTA)Figure 3-1: The Fabrication Process for MIS Capacitors- 32 -
3.3 Electrical Characteristics in the case of PDABefore the examinations of PMA, investigating the effects of PDAmust be done beforehand. The following is the results of PDA.3.3.1 Dependence on the Temperature of PDAFigure 3-2 shows the C-V characteristics dependent on thetemperature of PDA for La2O3 thin films. The surface treatment wasHF-last and the annealing temperatures from 300 o C to 450 o C were examinedrespectively, and all of them were annealed for 10 minutes in nitrogenambience and measured at 1 MHz.The hysteresis was not observed both as-deposited samples and PDAsamples. That means La2O3 films have good properties without mobilecharges like K + or Na + ion and with few charge traps at the state ofas-deposition. Moreover, it should be noted that the capacitance valueincreased with increase in the annealing temperature. This phenomenonsuggests two effects. One of them is that La2O3 films were densified by thehigher temperature annealing and their quality improved significantly.Another one is that high purity nitrogen ambient suppressed the growth ofinterfacial layer. On the other hand, however, it was found that the value ofVFB shift increased with increase in the annealing temperature.Figure 3-3 shows the J-V characteristics dependence on thetemperature of PDA for La2O3 thin films. The annealing temperatures from300 o C to 450 o C were examined respectively. It was also found that leakagecurrent decreased with increase in the annealing temperature. This resultsuggests that the higher temperature post deposition annealing decreasedthe defects in La2O3 films.Figure 3-4 shows the frequency dependence on C-V characteristics ofan as-deposited sample and PDA samples annealed at 300 o C, 400 o C and450 o C respectively. Ranges of frequency form 10 kHz to 1 MHz weremeasured. It was observed that the fluctuations of measuring value werealmost completely suppressed by PDA at 450 o C.- 33 -
Page 2: CONTENTSChapter 1 Introduction-----
Page 5 and 6: Chapter 1Introduction-1 -
Page 7 and 8: Miniaturization with a scaling fact
Page 9 and 10: Table 1-2: Electrical Properties fo
Page 11 and 12: LSI fabrication, such as activation
Page 13 and 14: Table 1-4 shows the properties of t
Page 15 and 16: 1.3 Purpose of My StudyIt is consid
Page 17 and 18: Chapter 2FabricationAndCharacteriza
Page 19 and 20: 2.1.1 1 Wet Cleaning Method of Sili
Page 21 and 22: 2.1.3 Molecular Beam Deposition (MB
Page 23 and 24: 2.1.4 Rapid Thermal Annealing (RTA)
Page 25 and 26: 2.1.5 Vacuum Evaporation MethodAlum
Page 27 and 28: 1 1 1 t 1 kTC = C + C = εε+ q ε
Page 29 and 30: In C-V curve, the two type of hyste
Page 31 and 32: 2.2.2 Leakage Current Density-Volta
Page 33 and 34: 2.2.3 Ellipsometry MethodEllipsomet
Page 35: 3.1 IntroductionIn this chapter, th
Page 39 and 40: Capacitance (µF/cm 2 )21Al/La O /
Page 41 and 42: Current Density [A/cm 2 ]10 2 10 1A
Page 43 and 44: 3.3.2 Effects of Chemical Oxidation
Page 45 and 46: 3.3.3 Dependence on the Annealing T
Page 47 and 48: Capacitance (µF/cm 2 )210Al_As-dep
Page 49 and 50: Capacitance (µF/cm 2 )210Al/La O /
Page 51 and 52: Al/La O / n-Si(100)/Al2 3 250 o C d
Page 53 and 54: As the summary of this sub-section,
Page 55 and 56: Current Density[A/cm 10 2 PDAAs-de
Page 57 and 58: Equivalent Oxide thickness [nm]32.5
Page 59 and 60: Figure 3-29 shows the plots of VFB
Page 61 and 62: 3.4.1.4 Dependence on the Ambience
Page 63 and 64: V Shift [V]FB0.60.40.20-0.2-0.4-0.6
Page 65 and 66: Capacitance (µF/cm 2 )21PDA 300 o
Page 67 and 68: case of aluminum electrodes as comp
Page 69 and 70: 3.4.2.2 Effects of Chemical Oxidati
Page 71 and 72: V Shift [V]FB-0.4-0.5-0.6-0.7-0.8-0
Page 73 and 74: 2.62.5EOT [nm]2.42.3As-depo.2.2PDA_
Page 75 and 76: Capacitance (µF/cm 2 )21Au_PMA_N2_
Page 77 and 78: 3.4.2.5 The comparison with the cas
Page 79 and 80: 3.4.3 Effects of PMA for Platinum U
Page 81 and 82: 4Pt/La O / n-Si(100)/Al2 3EOT [nm]3
Page 83 and 84: EOT [nm]2.82.62.42.221.81.6Pt/La O
Page 85 and 86: On the other hand, there was almost
Page 87 and 88:
V Shift [V]FB0.2Pt/La O / n-Si(100)
Page 89 and 90:
Capacitance (µF/cm 2 )21Pt/La O /
Page 91 and 92:
Capacitance (µF/cm 2 )21Pt_As-depo
Page 93 and 94:
Chapter 4Conclusions- 89 -
Page 95 and 96:
4.1.2 Summary of the Investigation
Page 97 and 98:
Table 4-2: Summary of my investigat
Page 99 and 100:
esults. The second is the time when
Page 101 and 102:
AluminumAl 2 O 3 or LaAlO 3Al Al Al
Page 103 and 104:
AcknowledgementIn the first place,
Page 105 and 106:
Reference[1] International Technolo
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Effect of Post Metallization Annealing for La 2 O 3 Thin Film

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