There has been significant interest recently in use of BaSrTiO3 (BST) thin films for integrated c... more There has been significant interest recently in use of BaSrTiO3 (BST) thin films for integrated capacitors; these devices have benefits for high frequency operations, particularly when high levels of charge or energy storage are required. We discuss the electrical properties of BST thin films grown by metalorganic chemical vapor deposition (MOCVD) which make them suitable for these applications, as well as the impact of processing conditions such as growth temperature on specific film properties. We have also examined addition of Zr in amounts ranging up to 20% to the BST films. X-Ray diffraction indicates that the Zr is incorporated into the BST lattice. Voltage withstanding capability, leakage and dielectric constant of the thin films have been measured as functions of deposition temperature and Zr content. Addition of Zr to BST films increases breakdown voltages by as much as a factor of two, to approximately 2 MV/cm, raising their energy storage density values to levels approach...
ABSTRACT Ceramics are rapidly being developed into a class of materials of importance in engineer... more ABSTRACT Ceramics are rapidly being developed into a class of materials of importance in engineering applications. This paper reviews developments, beginning with a historical perspective. It summarises properties of importance and discusses an approach to design of ceramic components. Developments in heat engines are discussed specifically, and the paper concludes with the current issues facing developers of engineering ceramics.
ABSTRACTWe demonstrate the feasibility of a Ta2O5-based metal-insulator-metal (MIM) capacitor mod... more ABSTRACTWe demonstrate the feasibility of a Ta2O5-based metal-insulator-metal (MIM) capacitor module which is integrated into the backend-of-the-line of a 0.5 μm CMOS process flow. The demonstration utilizes 6-inch wafers, sputtered Ta2O5 films with TaN and TiN electrodes, reactive ion etch (RIE) processes for defining the capacitor stack, and a metallization scheme which uses hot Al(Cu) and W plugs and a standard forming gas anneal (N2-5% H2). Acceptable electrical properties have been achieved within these processing constraints for the integrated MIM capacitor module, including specific capacitance (C/A) and leakage current density (J) of ≥ 5 fF/μm2 and ≤ 1 pA/pF-V, respectively. In addition, we compare the fundamental properties of the Ta2O5 dielectric with literature reports and point out that leakage mechanisms must be analyzed with care due to significant dielectric relaxation in the films under certain processing/measurement conditions. For the baseline integrated films, we ...
A dipole moment model explaining Vt tuning in HfSiON gated nFETs is proposed and its impact on pe... more A dipole moment model explaining Vt tuning in HfSiON gated nFETs is proposed and its impact on performance and reliability is presented. La, Sc, Er, and Sr dopants are utilized due to their differing electronegativities and ionic radii. These dopants tune Vt in the range of 250-600 mV. Vt tuning is found to be proportional to the net dipole moment
Advances in the development of high Tc superconducting thick film components and devices for micr... more Advances in the development of high Tc superconducting thick film components and devices for microwave, millimeterwave, and submillimeterwave applications have led to the optimization of laser patterning techniques. Plasma-sprayed superconducting thick films of YBaCuO materials on polycrystalline alumina were laser etched using an Nd: YAG laser (λ = 1.06 μm) in the Q-switched mode. Spatial uniformity of the surface elemental distribution of Y, Ba, Cu, and Al was observed in the underlying laser-etched area. An etch rate of 7.5 μm/scan was calculated at an optimized laser fluencc of 1.8 × 104 J/cm2 for a translation rate of 2.54 cm/s, having patterning widths ranging from 5–15 μm with a heat-affected zone of 3 μm. An absorption length of 18.3 μm for the Nd: YAG laser was determined to be suitable for patterning thick films (20–80 μm) for device fabrication. The results are further compared to CO2 (λ = 10.6 μm) laser etching for patterning (250 μm) thick films.
Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 1992
High quality, low growth temperature SiO2 thin films are necessary for the fabrication of submicr... more High quality, low growth temperature SiO2 thin films are necessary for the fabrication of submicron devices. A new deposition technique for SiO2 films utilizing chemical vapor deposition (CVD) of tetraethylorthosilicate (TEOS) in an ultrahigh vacuum chamber at low processing pressures (10−1 to 10−3 Torr) has been investigated. Ozone is introduced to provide a source of active oxygen. The oxide was characterized by ellipsometry, infrared absorption spectrometry, and etch rate. Films for comparison were grown using TEOS/oxygen and TEOS only. Results indicate that the active oxygen substantially reduces the deposition temperature. It was also found that the growth rate is strongly affected by the processing pressure at these very low pressures. The effect of important parameters (substrate temperature, TEOS/ozone ratio, oxidizing agent, and processing pressure) on the resultant oxide growth rate and properties are addressed. Our findings are compared to results reported in the literature for plasma‐enhanced ...
Interdigitated capacitors containing the field-tunable ferroelectric Ba 0.75 Sr 0.25 TiO 3 , poly... more Interdigitated capacitors containing the field-tunable ferroelectric Ba 0.75 Sr 0.25 TiO 3 , polycrystalline alumina substrates, and copper metallization have been fabricated. Dielectric layers were prepared by magnetron sputtering, while the Cu metallization was evaporated. The dielectric tunability of the Ba 0.75 Sr 0.25 TiO 3 was 40% at an applied electric field of 12 V/Am. This corresponds to a 3-Am electrode gap width and a 35 V dc bias. Low-frequency (1 MHz) loss tangent measurements indicate a dielectric Q (quality factor) of¨100 while microwave measurements reveal a zero bias device Q of¨30 at 26 GHz. These values are comparable or superior to numerous reports of barium strontium titanate interdigitated capacitors prepared using single crystalline substrates and noble metallization. As such, this technology is significantly less expensive and more amenable to large-volume manufacturing.
d acting on its behalf, a paid-up, non exclusive, irrevomble worldwide license in works, dmnbute ... more d acting on its behalf, a paid-up, non exclusive, irrevomble worldwide license in works, dmnbute mpm to the pbhc. and pa-form publicly and display publicly,by or -. This paper was submitted to the US-Japan Seminar on Dielectric and Piezoelectric Ceramics, Okinawa, Japan, held on November 3-5, 1999. ABSTRACT An approach for embedding high-K dielectric thin films into polymer packages has been developed. Pb0.g5L%.ls(fiOszTb.M)0.gsOs thin films were prepared by chemical solution deposition on 50 pm thick Ni-coated Cu foils. Sputter deposited Ni top electrodes completed the all base-metal capacitor stack. After high temperature N2 crystallization anneals, the PLZT composition showed reduction resistance while the base-metal foils remained flexible. Capacitance density and Loss tangent values range between 300 and 400 nF/cm2 and 0.01 and 0.02 from 1 to 1000 kHz respectively. These properties represent a 2 to 3 order of magnitude improvement over available embedded capacitor technologies ...
The processes involved in plasma and ion beam sputter-, electron evaporation-, and laser ablation... more The processes involved in plasma and ion beam sputter-, electron evaporation-, and laser ablation-deposition of high temperature superconducting thin films are critically reviewed. Recent advances in the development of these techniques are discussed in relation to basic physical phenomena, specific to each technique, which must be understood before high quality films can be produced. Low temperature processing of films is a common goal for each technique, particularly in relation to integrating high temperature superconducting films with the current microelectronics technology. Research is now demonstrating that the introduction of oxygen into the growing film, simultaneously with the deposition of the film components, is necessary to produce as-deposited superconducting films at relatively low substrate temperatures.
ABSTRACTIon beam sputter-deposition has been used to produce high temperature superconducting (HT... more ABSTRACTIon beam sputter-deposition has been used to produce high temperature superconducting (HTSC) thin films with controlled orientation. Room temperature scanning tunneling microscopy (STM) studies of ion beam sputter-deposited Y-Ba-Cu-O thin films indicate that the growth mode depends on whether the films are a- or c-axis oriented. The c-axis oriented films appear to grow by a screw dislocation mechanism, producing layered spirals similar to those observed in films grown by plasma sputtering and laser ablation-deposition. STM images of the a-axis oriented films show a growth mode which appears to produce layered structures perpendicular to the substrate with no spirals. Scanning tunneling spectroscopy (STS) studies of the a- and c-axis oriented films tend to reflect the anisotropy of the Y-Ba-Cu-O structure. Both the c-axis and the a-axis oriented films have semiconducting characteristics, possibly due to a native oxide, with a band gap estimated to be 1.4 eV. The c-axis orient...
There has been significant interest recently in use of BaSrTiO3 (BST) thin films for integrated c... more There has been significant interest recently in use of BaSrTiO3 (BST) thin films for integrated capacitors; these devices have benefits for high frequency operations, particularly when high levels of charge or energy storage are required. We discuss the electrical properties of BST thin films grown by metalorganic chemical vapor deposition (MOCVD) which make them suitable for these applications, as well as the impact of processing conditions such as growth temperature on specific film properties. We have also examined addition of Zr in amounts ranging up to 20% to the BST films. X-Ray diffraction indicates that the Zr is incorporated into the BST lattice. Voltage withstanding capability, leakage and dielectric constant of the thin films have been measured as functions of deposition temperature and Zr content. Addition of Zr to BST films increases breakdown voltages by as much as a factor of two, to approximately 2 MV/cm, raising their energy storage density values to levels approach...
ABSTRACT Ceramics are rapidly being developed into a class of materials of importance in engineer... more ABSTRACT Ceramics are rapidly being developed into a class of materials of importance in engineering applications. This paper reviews developments, beginning with a historical perspective. It summarises properties of importance and discusses an approach to design of ceramic components. Developments in heat engines are discussed specifically, and the paper concludes with the current issues facing developers of engineering ceramics.
ABSTRACTWe demonstrate the feasibility of a Ta2O5-based metal-insulator-metal (MIM) capacitor mod... more ABSTRACTWe demonstrate the feasibility of a Ta2O5-based metal-insulator-metal (MIM) capacitor module which is integrated into the backend-of-the-line of a 0.5 μm CMOS process flow. The demonstration utilizes 6-inch wafers, sputtered Ta2O5 films with TaN and TiN electrodes, reactive ion etch (RIE) processes for defining the capacitor stack, and a metallization scheme which uses hot Al(Cu) and W plugs and a standard forming gas anneal (N2-5% H2). Acceptable electrical properties have been achieved within these processing constraints for the integrated MIM capacitor module, including specific capacitance (C/A) and leakage current density (J) of ≥ 5 fF/μm2 and ≤ 1 pA/pF-V, respectively. In addition, we compare the fundamental properties of the Ta2O5 dielectric with literature reports and point out that leakage mechanisms must be analyzed with care due to significant dielectric relaxation in the films under certain processing/measurement conditions. For the baseline integrated films, we ...
A dipole moment model explaining Vt tuning in HfSiON gated nFETs is proposed and its impact on pe... more A dipole moment model explaining Vt tuning in HfSiON gated nFETs is proposed and its impact on performance and reliability is presented. La, Sc, Er, and Sr dopants are utilized due to their differing electronegativities and ionic radii. These dopants tune Vt in the range of 250-600 mV. Vt tuning is found to be proportional to the net dipole moment
Advances in the development of high Tc superconducting thick film components and devices for micr... more Advances in the development of high Tc superconducting thick film components and devices for microwave, millimeterwave, and submillimeterwave applications have led to the optimization of laser patterning techniques. Plasma-sprayed superconducting thick films of YBaCuO materials on polycrystalline alumina were laser etched using an Nd: YAG laser (λ = 1.06 μm) in the Q-switched mode. Spatial uniformity of the surface elemental distribution of Y, Ba, Cu, and Al was observed in the underlying laser-etched area. An etch rate of 7.5 μm/scan was calculated at an optimized laser fluencc of 1.8 × 104 J/cm2 for a translation rate of 2.54 cm/s, having patterning widths ranging from 5–15 μm with a heat-affected zone of 3 μm. An absorption length of 18.3 μm for the Nd: YAG laser was determined to be suitable for patterning thick films (20–80 μm) for device fabrication. The results are further compared to CO2 (λ = 10.6 μm) laser etching for patterning (250 μm) thick films.
Journal of Vacuum Science & Technology A: Vacuum, Surfaces, and Films, 1992
High quality, low growth temperature SiO2 thin films are necessary for the fabrication of submicr... more High quality, low growth temperature SiO2 thin films are necessary for the fabrication of submicron devices. A new deposition technique for SiO2 films utilizing chemical vapor deposition (CVD) of tetraethylorthosilicate (TEOS) in an ultrahigh vacuum chamber at low processing pressures (10−1 to 10−3 Torr) has been investigated. Ozone is introduced to provide a source of active oxygen. The oxide was characterized by ellipsometry, infrared absorption spectrometry, and etch rate. Films for comparison were grown using TEOS/oxygen and TEOS only. Results indicate that the active oxygen substantially reduces the deposition temperature. It was also found that the growth rate is strongly affected by the processing pressure at these very low pressures. The effect of important parameters (substrate temperature, TEOS/ozone ratio, oxidizing agent, and processing pressure) on the resultant oxide growth rate and properties are addressed. Our findings are compared to results reported in the literature for plasma‐enhanced ...
Interdigitated capacitors containing the field-tunable ferroelectric Ba 0.75 Sr 0.25 TiO 3 , poly... more Interdigitated capacitors containing the field-tunable ferroelectric Ba 0.75 Sr 0.25 TiO 3 , polycrystalline alumina substrates, and copper metallization have been fabricated. Dielectric layers were prepared by magnetron sputtering, while the Cu metallization was evaporated. The dielectric tunability of the Ba 0.75 Sr 0.25 TiO 3 was 40% at an applied electric field of 12 V/Am. This corresponds to a 3-Am electrode gap width and a 35 V dc bias. Low-frequency (1 MHz) loss tangent measurements indicate a dielectric Q (quality factor) of¨100 while microwave measurements reveal a zero bias device Q of¨30 at 26 GHz. These values are comparable or superior to numerous reports of barium strontium titanate interdigitated capacitors prepared using single crystalline substrates and noble metallization. As such, this technology is significantly less expensive and more amenable to large-volume manufacturing.
d acting on its behalf, a paid-up, non exclusive, irrevomble worldwide license in works, dmnbute ... more d acting on its behalf, a paid-up, non exclusive, irrevomble worldwide license in works, dmnbute mpm to the pbhc. and pa-form publicly and display publicly,by or -. This paper was submitted to the US-Japan Seminar on Dielectric and Piezoelectric Ceramics, Okinawa, Japan, held on November 3-5, 1999. ABSTRACT An approach for embedding high-K dielectric thin films into polymer packages has been developed. Pb0.g5L%.ls(fiOszTb.M)0.gsOs thin films were prepared by chemical solution deposition on 50 pm thick Ni-coated Cu foils. Sputter deposited Ni top electrodes completed the all base-metal capacitor stack. After high temperature N2 crystallization anneals, the PLZT composition showed reduction resistance while the base-metal foils remained flexible. Capacitance density and Loss tangent values range between 300 and 400 nF/cm2 and 0.01 and 0.02 from 1 to 1000 kHz respectively. These properties represent a 2 to 3 order of magnitude improvement over available embedded capacitor technologies ...
The processes involved in plasma and ion beam sputter-, electron evaporation-, and laser ablation... more The processes involved in plasma and ion beam sputter-, electron evaporation-, and laser ablation-deposition of high temperature superconducting thin films are critically reviewed. Recent advances in the development of these techniques are discussed in relation to basic physical phenomena, specific to each technique, which must be understood before high quality films can be produced. Low temperature processing of films is a common goal for each technique, particularly in relation to integrating high temperature superconducting films with the current microelectronics technology. Research is now demonstrating that the introduction of oxygen into the growing film, simultaneously with the deposition of the film components, is necessary to produce as-deposited superconducting films at relatively low substrate temperatures.
ABSTRACTIon beam sputter-deposition has been used to produce high temperature superconducting (HT... more ABSTRACTIon beam sputter-deposition has been used to produce high temperature superconducting (HTSC) thin films with controlled orientation. Room temperature scanning tunneling microscopy (STM) studies of ion beam sputter-deposited Y-Ba-Cu-O thin films indicate that the growth mode depends on whether the films are a- or c-axis oriented. The c-axis oriented films appear to grow by a screw dislocation mechanism, producing layered spirals similar to those observed in films grown by plasma sputtering and laser ablation-deposition. STM images of the a-axis oriented films show a growth mode which appears to produce layered structures perpendicular to the substrate with no spirals. Scanning tunneling spectroscopy (STS) studies of the a- and c-axis oriented films tend to reflect the anisotropy of the Y-Ba-Cu-O structure. Both the c-axis and the a-axis oriented films have semiconducting characteristics, possibly due to a native oxide, with a band gap estimated to be 1.4 eV. The c-axis orient...
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Papers by Angus Kingon