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

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EOT [nm]2.221.81.6Al/La O / n-Si(100)/Al2 3HF-last 250 o C depo.As-depo. & PDA300 o C400 o CAs-depo.450 o C Good1.4-1.2 -1 -0.8 -0.6V Shift [V]FBFigure 3-8: VFB shift – EOT PlotsCapacitance (µF/cm 2 )21Al/La O / n-Si(100)/Al2 3 250 o C depo300 o C PDAAl/La O / n-Si(100)/Al2 3 Al/La O / n-Si(100)/Al2 3 250 o C depo250 o C depo400 o C PDA450 o C PDA0-1.5 -1 -0.5 0 0.5-1.5 -1 -0.5 0 0.5-1.5 -1 -0.5 0 0.5Voltage (V)Voltage (V)Voltage (V)(a) 300 o C (b) 400 o C (c) 450 o CFigure 3-9: The C-V characteristics Dependent on the rising ratio of PMA at(a) 300 o C (b) 400 o C (c) 450 o C- 38 -
3.3.2 Effects of Chemical Oxidation Treatment for PDAIt is anticipated that Chemical oxidation treatment would bring thebetter characteristics in many ways because SiO2 is magnificently stable athigher temperature, and also have larger band gap and good matching withsilicon surface, which is the most important part in terms of electricalcharacteristics. Some excellent results have already been reported by usingchemical oxidation. On the basis of the facts, the effect of chemicaloxidation treatment for La2O3 thin film was examined.Figure 3-10 shows the comparison of C-V characteristics betweenHF-last treatment and chemical oxidation treatment. It is observed thatthe capacitance value of the samples treated by chemical oxidation wasmaintained on a level with the samples treated by HF-last although extralayer having lower dielectric constant was inserted. Two reasons can beassumed for this phenomenon. One is owing to a formation of the goodsilicate layer. It is conceivable that La2O3 reacted with chemically formedSiO2 through thermal process and this reaction would create the goodsilicate layer. Another one is a formation of thinner layer. Although thesesamples were fabricated by same deposition, there is a possibility that theyhave different thickness. The samples treated by HF-last were deposited onsilicon substrates. On the other hand, however, the samples treated bychemical oxidation were deposited on SiO2. The deposition rate mightchange on what La2O3 films were deposited.Figure 3-11 shows the comparison of J-V characteristics betweenHF-last treatment and chemical oxidation treatment. It is confirmed thatchemical oxidation treatment suppressed the leakage current about 2 ordersof magnitude at +1 V as compared with HF-last treatment. Therefore, itseems proper that chemical oxidation treatment brought a formation of thegood silicate layer and that led to the suppression of the leakage current withmaintaining the capacitance value. From these results, It can be said thatchemical oxidation treatment was quite effective for La2O3 thin films.- 39 -
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 and 36: 3.1 IntroductionIn this chapter, th
Page 37 and 38: 3.3 Electrical Characteristics in t
Page 39 and 40: Capacitance (µF/cm 2 )21Al/La O /
Page 41: Current Density [A/cm 2 ]10 2 10 1A
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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