Compensation doping of Ba0.7Sr0.3TiO3 thin films

Copel, M.; Baniecki, J. D.; Duncombe, P. R.; Kotecki, David E.; Laibowitz, R. B.; Neumayer, Deborah A.; Shaw, T. M.

doi:10.1063/1.122297

Cited by 50 publications

(29 citation statements)

References 10 publications

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“…[20][21][22] Therefore, it was considered that the leakage current density of BTT films could be improved by doping the Mn ions. Figure 5 shows the leakage current density of the x mol % Mn-doped BTT films with 0 ഛ x ഛ 10.0 grown at 300°C under 80.0 Pa OP.…”

Section: Resultsmentioning

confidence: 99%

Oxygen Pressure and Mn-Doping Effects on the Structure and Leakage Current of Bi[sub 6]Ti[sub 5]TeO[sub 22] Thin Film

Choi

Cho

et al. 2008

J. Electrochem. Soc.

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Te ions existed as Te 6+ in the Bi 6 Ti 5 TeO 22 ͑BTT͒ film grown at 300°C under a high oxygen pressure ͑OP͒ of 80.0 Pa and contributed to the formation of the crystalline BTT phase after subsequent annealing at 600°C. However, for the BTT film grown under a low OP of 53.3 Pa ͑or 9.33 Pa͒, Te 6+ ions, were converted to Te 4+ ions, which induced the phase transition of the BTT phase to the pseudo-Bi 4 Ti 3 O 12 and pseudo-Bi 2 Ti 2 O 7 phases after annealing at 600°C. The leakage current density decreased with increasing OP during the growth due to the decreased number of oxygen vacancies. The breakdown voltage also improved with increasing OP during the deposition. The Mn ions introduced in the BTT films by Mn doping existed as Mn 2+ or Mn 4+ and acted as the acceptors. This Mn doping to 10 mol % also reduced the leakage current density and increased the breakdown voltage by decreasing the number of intrinsic oxygen vacancies.Investigations on dielectric thin films with a high dielectric constant ͑k͒ which can be deposited at low temperatures ͑ഛ300°C͒ have multiplied for applications to the embedded decoupling capacitors for printed circuit board ͑PCB͒ and the gate insulators of ZnObased, thin-film transistors for organic light-emitting diodes ͑OLEDs͒ on plastic substrate. 1-3 The radio-frequency ͑rf͒ or analog/ mixed metal-insulator-metal ͑MIM͒ capacitors in semiconductor devices also require a dielectric thin film with low processing temperatures due to the limitation of the very large-scale integration back-end line integration temperature ͑Ͻ400°C͒. Previously, ͑Ba,Sr͒TiO 3 , Ta 2 O 5 , TaTiO, and BaSm 2 Ti 4 O 12 films grown at low temperatures were used as the gate insulators for OLEDs and rf MIM capacitors but suffered from a low-k value. 4-8 Ca-doped Pb͑Zr,Ti͒O 3 films were grown for use as the embedded capacitors for PCBs, but their growth temperature was too high for such application. 9 Recently, Bi-based, dielectric thin films such as Bi 6 Ti 5 TeO 22 ͑BTT͒, 10 Bi 5 Nb 3 O 15 , 11 and Bi 1.5 Zn 1.0 Nb 1.5 O 7 1,3,12 have been extensively studied because of their achievement of high-k value with low deposition temperatures. In particular, the high-k value of 69 with a low dissipation factor ͑Ͻ1.3%͒ 10 obtained by BTT films grown at 300°C using sputtering demonstrated their promise as a good candidate material for high-k dielectric films with low processing temperatures. However, their leakage current density was relatively high with a low breakdown voltage, 10 thereby necessitating the improvement of their electrical properties before the application of such BTT films. Furthermore, the structure of the BTT films was considerably influenced by the valence of the Te ions, which was determined by the oxygen pressure ͑OP͒ during the fabrication processes. 10 However, no detailed investigation on the variation of the crystal structure of the BTT film with OP has yet been conducted.In this work, BTT films were grown using pulsed laser deposition ͑PLD͒ and annealed under various OPs. The PLD method was selected...

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Section: Resultsmentioning

confidence: 99%

Oxygen Pressure and Mn-Doping Effects on the Structure and Leakage Current of Bi[sub 6]Ti[sub 5]TeO[sub 22] Thin Film

Choi

Cho

et al. 2008

J. Electrochem. Soc.

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“…In order to enhance the dielectric properties of BST thin films, research efforts into the metal (e.g., Mn, Al, Mg, of Ni) doping of a BST host have been widely reported. 7,[9][10][11][12][13] One explanation for the leakage current reduction is that the doping results in an increase of the potential barrier height at the interface between BST and electrodes and therefore decreases the Schottky emission current. 9 Another explanation for the current reduction of Ni or Mn doping is that the FowlerNordheim tunneling current is significant suppression.…”

Section: Introductionmentioning

confidence: 99%

“…7,[9][10][11][12][13] One explanation for the leakage current reduction is that the doping results in an increase of the potential barrier height at the interface between BST and electrodes and therefore decreases the Schottky emission current. 9 Another explanation for the current reduction of Ni or Mn doping is that the FowlerNordheim tunneling current is significant suppression. 7,13 In our recent work, 14 we reported the capacitors employing BZN/BST bilayered thin films exhibiting large tunability of capacitance and high Q-factor.…”

Section: Introductionmentioning

confidence: 99%

Enhanced leakage current performance and conduction mechanisms of Bi1.5Zn1.0Nb1.5O7/Ba0.5Sr0.5TiO3 bilayered thin films

Jiang

Gao

et al. 2012

Journal of Applied Physics

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The Bi1.5Zn1.0Nb1.5O7 (BZN)/Ba0.5Sr0.5TiO3 (BST) bilayered films and BST thin films were prepared via radio frequency (RF) magnetron sputtering, and the leakage current behaviors of the films were investigated. Lower leakage currents of BZN/BST bilayered films were achieved compared with that of BST thin films, especially in the high field region. The potential barrier height of top contact is increased by insertion of a BZN layer in between BST and top Pt-electrodes, which might be responsible for the current reduction of BZN/BST under negative biases (positive voltage applied to bottom electrodes). For the case of positive biases, BZN/BST showed a significant increase in the threshold electric field of Poole-Frenkel emission compared with that of BST, resulting in a current decrease in BZN/BST than that in BST. For the BZN/BST bilayered films at 300 K, since the Schottky emission, Fowler-Nordheim tunneling and Poole-Frenkel emission occur in an extremely high electric field, the leakage current is governed by Ohmic conductivity behavior in a wide applied field of up to ∼1 MV/cm.

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“…In previous studies, Mn ions have been used as acceptor ions to improve the electrical properties of thin films and multilayer capacitors, in which intrinsic oxygen vacancies are the major defects that degrade the electrical properties of the devices. [24][25][26] Therefore, Mn ions were doped into the B 2 T 2 films grown at 300 C under 740 mTorr and annealed under 100 Torr OP in order to further improve the electrical properties of the films. Figure 5 shows the leakage current density for the x mol % Mn-doped B 2 T 2 films (with 0.0 x 20.0) grown at 300 C under 740 mTorr OP and subsequently annealed at 300 C under 100 Torr OP.…”

Section: Resultsmentioning

confidence: 99%

Electrical Properties of Bi2Ti2O7 Thin Films Grown at Low Temperature by the Pulsed Laser Deposition

Kang¹,

Kim²,

Sun³

et al. 2011

Electrochem. Solid-State Lett.

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A crystalline Bi 2 Ti 2 O 7 (B 2 T 2 ) film with a high dielectric constant (e r ) of 67.2 was formed even at 300 C when the oxygen pressure (OP) exceeded 600 mTorr, even though the Bi 4 Ti 3 O 12 target was used. The Mn-doping improved the electrical properties of the B 2 T 2 films by producing the doubly ionized, extrinsic oxygen vacancies, which reduced the number of intrinsic oxygen vacancies. The B 2 T 2 film containing 20 mol% of Mn ions, which was annealed under an OP of 75.0 Torr, exhibited a low leakage current density of 5 Â 10 À7 A/cm 2 at 0.5 MV/cm 2 and a large e r ($73) with a low tan d ($1.3%).Dielectric thin films with a high dielectric constant (e r ) that can be fabricated at temperatures below 350 C have attracted increasing research attention because they can be applied to the decoupling embedded capacitors in printed circuit boards, which require a low processing temperature and a high capacitance. These dielectric thin films can also be used in the metal-insulator-metal (MIM) capacitors for radio frequency (RF) or analog/mixed applications which need a low processing temperature ( 400 C) due to the limitation of the very large scale integration back-end line processes. 1 The gate insulators of organic thin-film transistors (OTFTs) also require a high e r dielectric thin film with a low fabrication temperature ( 350 C). Pb(Zr,Ti)O 3 and (Pb,La)(Zr,Ti)O 3 thin films were successfully grown on a pure or Ni-coated Cu substrate, but their processing temperature was too high at approximately 600-650 C for applications in embedded passive capacitors. 2,3 Furthermore, amorphous Nb 2 O 5 (e r ¼ $40), 4 TaTiO (e r ¼ 45), 5-7 and Pr 2 O 3 (Ref. 8) films grown at low temperatures ( 400 C) have been used for RF MIM capacitors, but their e r values were relatively low. Amorphous SiO 2 , 9 CeO 2 , 10 Ta 2 O 5 , 11 and Y 2 O 3 (Ref. 12) films have been used as the gate insulators of the OTFTs, but again, their e r values were unsatisfactory. Since the crystalline phase generally has a high e r value compared with the amorphous phase, finding a method that is capable of growing the crystalline phase at low temperatures is important for obtaining dielectric films with high e r values.Recently, Bi 2 O 3 -based thin films, such as Bi 1.5 Zn 1.0 Nb 1.5 O 7 , 13-15 Bi 4 Ti 3 O 12 (B 4 T 3 ), 16 and Bi 5 Nb 3 O 15 films, have been investigated because they are grown at low temperatures with relatively high e r values, even though they were in amorphous phase. If the Bi 2 O 3 -based thin films with a crystalline phase can be grown at temperatures lower than 350 C, dielectric films with higher e r values can be obtained. According to the previous work on the B 4 T 3 thin film grown by a pulsed laser deposition (PLD) using a B 4 T 3 target, the amorphous B 4 T 3 thin film was obtained at 300 C, while the crystalline Bi 2 Ti 2 O 7 (B 2 T 2 ) and Bi 2 Ti 4 O 11 phases were developed in the films grown at 400-500 and 600 C, respectively. 16 Finally, a B 4 T 3 crystalline phase was formed in the film grown at 700 C. 16 ...

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Compensation doping of Ba0.7Sr0.3TiO3 thin films

Cited by 50 publications

References 10 publications

Oxygen Pressure and Mn-Doping Effects on the Structure and Leakage Current of Bi[sub 6]Ti[sub 5]TeO[sub 22] Thin Film

Oxygen Pressure and Mn-Doping Effects on the Structure and Leakage Current of Bi[sub 6]Ti[sub 5]TeO[sub 22] Thin Film

Enhanced leakage current performance and conduction mechanisms of Bi1.5Zn1.0Nb1.5O7/Ba0.5Sr0.5TiO3 bilayered thin films

Electrical Properties of Bi2Ti2O7 Thin Films Grown at Low Temperature by the Pulsed Laser Deposition

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