Abstract……………………………………………………I Contents……………………………………………………VIII Table Captions……………………………………………XI Figure Captions…………………………………………XII Chapter 1 Introduction…………………………………1 Chapter 2 Theory……………………………………… 10 2-1 Measurement of Dielectric Resonator…………10 2-2 Thin Film……………………………………………11 2-2-1 Surface Morphology of Film …………………11 2-2-2 I-V Characteristic of Film …………………12 2-2-3 C-V Characteristic of Film………………14 2-3 Basic Theory of Microwave Filter ……………17 Chapter 3 Investigation of Nano-Scaled Alumina Ceramics…21 3-1 Experimental Procedures……………………………………………21 3-2 Results and Discussion……………………………………………23 3-2-1 Nano-Scaled α-Al2O3 Ceramics………………………………………………23 3-2-2 Nano-Scaled (α+θ)-Al2O3 Ceramics…………………………………………25 3-2-3 Nano-Scaled α-Al2O3 and TiO2 Ceramics……………………………………28 Chapter 4 Microwave Dielectric Properties of (Mg0.95Zn0.05)TiO3 System…………..35 4-1 Experimental Procedures……………………………………………………………..35 4-2 Results and Discussion……………………………………………………………….36 4-2-1 (1-x)(Mg0.95Zn0.05)TiO3-xSrTiO3 Ceramic System…………………………….36 4-2-2 (1-x)(Mg0.95Zn0.05)TiO3-x(Na0.5La0.5)TiO3 Ceramic System…………………...40 4-2-3 (1-x)(Mg0.95Zn0.05)TiO3-x(Na0.5Nd0.5)TiO3 Ceramic System…………………..43 Chapter 5 RF Magnetron Sputtered Alpha Alumina (α-Al2O3) Films Using Nano-scaled Target Powders…………………………………………….46 5-1 Experimental Procedures……………………………………………………………..46 5-1-1 Clean Substrate…………………………………………………………………46 5-1-2 Deposition Process……………………………………………………………..47 5-1-3 Analysis of Physical Properties of Films……………………………………….47 5-1-4 Analysis of Electrical Properties of Films……………………………………...48 5-2 Results and Discussions………………………………………………………………48 5-2-1 Crystal Structure and Composition……………………………………………..48 5-2-2 Microstructure and Surface Morphology……………………………………….49 5-2-3 Electrical Properties of Alpha Alumina Thin Films……………………………50 Chapter 6 Using Low Loss Ceramic Substrates to Design Bandpass Filter with Zero-Degree Feed Structure……………………………………………….53 6-1 Stepped Impedance Resonator (SIR)…………………………………………………53 6-1-1 Basic Structure of SIR………………………………………………………….53 6-1-2 Resonance Conditions and Resonator Electrical Length……………………….54 6-1-3 Theory of the Zero Degree Feed structure……………………………………...55 6-2 Filter Design…………………………………………………………………………..57 6-3 Simulated and Measured Results……………………………………………………..58 Chapter 7 Conclusions and Future Works……………………………………………..60 7-1 Conclusions………………………………………...60 7-2 Future Works……………………………………….65 References………………………………………………..66 Tables………………………………………………….72 Figures…………………………………………………77 Table Captions Table 1-1 The recent development for microwave dielectric materials…………………..72 Table 3-1 Basic physical properties of starting nano (α+θ)-Al2O3 powders……………...73 Table 3-2 Relations of relative density of green samples and pressing pressure for nano-scaled alpha alumina………………………………………………….73 Table 3-3 Impurities analyses of nano α-Al2O3 powders of purity 99.883%......................73 Table 3-4 The EDS data of the nano α-Al2O3 ceramics with TiO2 additions sintered at 1400oC for 4 h……………………………………………………..74 Table 3-5 Comparison of microwave dielectric properties of sintered Al2O3…………….74 Table 4-1 EDX data of 96MZST ceramics for spots A, B, C, and D……………………...75 Table 4-2 The EDX data of the 96MZST ceramics sintered from 1225 to 1350oC and the surfaces of all the samples coated by carbon…………………………75 Table 4-3 Lattice parameters of (1-x)(Mg0.95Zn0.05)TiO3-xSrTiO3 ceramics sintered at 1300oC………………………………………………………………75 Table 4-4 Microwave dielectric properties of (1-x)(Mg0.95Zn0.05)TiO3-xSrTiO3 ceramic system sintered at 1300C for 4 h……………………………………..76 Table 5-1 Sputtering parameters in the experiment……………………………………….76 Table 6-1 Dimensions of microstrip bandpass filter with different ceramic substrates……………………………………………….76 Figure Captions Fig. 2-1 Courtney holder as a test set for measuring microwave dielectric properties…...77 Fig. 2-2 Schematic representation of the general physical structure of the thin film prepared under low mobility condition………………………………………………….....77 Fig. 2-3 A schematic diagram displaying (a) the Poole-Frenkel (PF) and (b) the enhanced Schottky emission transport mechanism…………………………………………78 Fig. 2-4 Energy bands, and charge distribution in a MIS structure under various bias conditions, in the absence of the surface states and work function difference (Ideal Case)……………………………………………………………………………...78 Fig. 2-5 Typical CV plot of high- frequency for n-type substrate…………………….......79 Fig. 2-6 Three types of the filters (a) Maximally Flat (b) Chebyshev (c) Elliptic Function……………………………………………………………..79 Fig. 2-7 Low pass prototype filter…………………………………………………………80 Fig. 2-8 Bandpass filter circuits using J and K inverters…………………………………..80 Fig. 3-1 The particle size distribution of the nano alpha alumina powders………………..81 Fig. 3-2 The sintering shrinkage curve of the nano alpha alumina ceramics……………...81 Fig. 3-3 XRD patterns of nano alpha alumina ceramics sintered at (a) 1350, (b) 1400, (c) 1450, (d) 1500, and (e) 1550℃ for 4 h…………………………………………..82 Fig. 3-4 SEM micrographs of nano alpha alumina ceramics sintered at (a) 1350, (b) 1400, (c) 1450, (d) 1500, and (e) 1550℃ for 4 h…………………………………….....83 Fig. 3-5 Relative densities of nano alpha alumina ceramics sintered at different temperatures……………………………………………………………………84 Fig. 3-6 Dielectric constant of nano alpha alumina ceramics sintered at different temperatures……………………………………………………………………84 Fig. 3-7 Q × f values of nano alpha alumina ceramics sintered at different temperatures…85 Fig. 3-8 Temperature coefficient of resonant frequency ( ) of nano alpha alumina ceramics sintered at different temperatures……………………………………..85 Fig. 3-9 (a) The particle size distribution of starting nano (α+θ)-Al2O3 powders (b) The XRD phase identification of starting nano (α+θ)-Al2O3 powders………………86 Fig. 3-10 Thermal shrinkage curve of the green compact prepared by starting nano (α+θ)-Al2O3 powder ……………………………………………………………..87 Fig. 3-11 X-ray diffraction patterns of the nano (α+θ)-Al2O3 ceramics sintered at 1400℃ for (a) 2 h (b) 4 h (c) 8 h………………………………………………………...87 Fig. 3-12 SEM micrographs (×30k) of the specimens sintered at 1400℃ using nano (α+θ)-Al2O3 for (a) 2 h (b) 4 h (c) 8 h…………………………………………88 Fig. 3-13 The relative densities of the nano (α+θ)-Al2O3 ceramics as a function of its sintering time at 1400℃………………………………………………………...89 Fig. 3-14 The dielectric constant of the nano (α+θ)-Al2O3 ceramics as a function of its sintering time at 1400℃…………………………………………………….....89 Fig. 3-15 The Q × f value of the nano (α+θ)-Al2O3 ceramics as a function of its relative density………………………………………………………………………....90 Fig. 3-16 The temperature coefficients of resonant frequency ( ) of the nano (α+θ)-Al2O3 ceramics as a function of its sintering time at 1400℃………………………...90 Fig. 3-17 The SEM micrograph of nanometer-scaled (a) α-Al2O3 and (b) TiO2 powders...91 Fig. 3-18 Shrinkage of the nano α-Al2O3 samples with 0.25-8 wt% TiO2 additions……...91 Fig. 3-19 XRD patterns of the nano α-Al2O3 ceramics with (a) 0.25 wt% (b) 0.5 wt% (c) 8 wt% TiO2 additions sintered at different sintering temperatures…………….....92 Fig. 3-20 XRD patterns of the nano α-Al2O3 ceramics with TiO2 additions sintered at 1400oC for 4 h…………………………………………………………………93 Fig. 3-21 SEM micrographs of the sintered specimens using nano α-Al2O3 ceramics with (a) 0.25 wt% (b) 0.5 wt% (c) 1 wt% (d) 2 wt% (e) 4 wt% (f) 8 wt% TiO2 additions at 1400oC/4h…………………………………………………………………...94 Fig. 3-22 The apparent density of the nano α-Al2O3 ceramics with TiO2 additions as a function of its sintering temperature for 4 h…………………………………...95 Fig. 3-23 The dielectric constants of the nano α-Al2O3 ceramics with TiO2 additions as a function of its sintering temperature for 4 h………………………………….....95 Fig. 3-24 The Q × f values of the nano α-Al2O3 ceramics with TiO2 additions as a function of its sintering temperature for 4 h………………………………………….....96 Fig. 3-25 The temperature coefficients of resonant frequency ( ) of the nano α-Al2O3 ceramics with TiO2 additions as a function of its sintering temperature for 4 h……………………………………………………………………….....96 Fig. 3-26 Apparent densities of the nano α-Al2O3 ceramics as a function of TiO2 addition sintered at 1400oC for 4 h…………………………………………………….....97 Fig. 3-27 Q × f values of the nano α-Al2O3 ceramics as a function of TiO2 addition sintered at 1400oC for 4 h………………………………………………………………..97 Fig. 3-28 Energy dispersion spectrum (EDS) analysis of the Al2TiO5 phase……………..98 Fig. 4-1 X-ray diffraction patterns of 96MZST ceramics sintered at different sintering temperatures for 4 h…………………………………………………………......99 Fig. 4-2 SEM photographs of 96MZST ceramics sintered at (a) 1225C (b) 1250C (c) 1275C (d) 1300C (e) 1325C (f) 1350C for 4 h……………………………100 Fig. 4-3 Marks of SEM for the 96MZST ceramics sintered at 1300oC…………………..101 Fig. 4-4 Typical energy dispersive X-ray (EDX) analysis of the sintered specimen…….101 Fig. 4-5 Apparent density of 96MZST ceramics as a function of its sintering temperature……………………………………………………………………...102 Fig. 4-6 Dielectric constant of 96MZST ceramics as a function of its sintering temperature……………………………………………………………………..102 Fig. 4-7 Q × f value of 96MZST ceramics as a function of its sintering temperature…...103 Fig. 4-8 value of (1-x)(Mg0.95Zn0.05)TiO3-xSrTiO3 ceramic system sintered at 1300C for 4 h with different x values…………………………………………………..103 Fig. 4-9 X-ray diffraction patterns of 88MZNLT ceramics sintered at different sintering temperatures for 4 h……………………………………………………………..104 Fig. 4-10 SEM photographs of 88MZNLT ceramics sintered at (a) 1250℃ (b) 1275℃ (c) 1300℃ (d) 1325℃ (e) 1350℃ for 4 h………………………………………...105 Fig. 4-11 (a) the marks of SEM for the 88MZNLT ceramics sintered at 1300oC (b) EDX data of 88MZNLT ceramics for spots A ~ C…………………………………106 Fig. 4-12 Apparent density of (1-x)(Mg0.95Zn0.05)TiO3-x(Na0.5La0.5)TiO3 ceramic system as a function of its sintering temperature………………………………………..108 Fig. 4-13 Dielectric constant of (1-x)(Mg0.95Zn0.05)TiO3-x(Na0.5La0.5)TiO3 ceramic system as a function of its sintering temperature…………………………………….108 Fig. 4-14 Q × f value of (1-x)(Mg0.95Zn0.05)TiO3-x(Na0.5La0.5)TiO3 ceramic system as a function of its sintering temperature…………………………………………109 Fig. 4-15 value of (1-x)(Mg0.95Zn0.05)TiO3-x(Na0.5La0.5)TiO3 ceramic system as a function of its x values……………………………………………………….109 Fig. 4-16 X-ray diffraction patterns of 84MZNNT ceramics sintered at different sintering temperatures for 4 h…………………………………………………………..110 Fig. 4-17 SEM photographs of 84MZNNT ceramics sintered at (a) 1250℃ (b) 1275℃ (c) 1300℃ (d) 1325℃ (e) 1350℃ for 4 h……………………………………….111 Fig. 4-18 (a) the marks of SEM for the 84MZNNT ceramics sintered at 1300oC (b) EDX data of 84MZNNT ceramics for spots A ~ C………………………………...112 Fig. 4-19 Apparent density of (1-x)(Mg0.95Zn0.05)TiO3-x(Na0.5Nd0.5)TiO3 ceramic system as a function of its sintering temperature………………………………………..114 Fig. 4-20 Dielectric constant of (1-x)(Mg0.95Zn0.05)TiO3-x(Na0.5Nd0.5)TiO3 ceramic system as a function of its sintering temperature…………………………………….114 Fig. 4-21 Q × f value of (1-x)(Mg0.95Zn0.05)TiO3-x(Na0.5Nd0.5)TiO3 ceramic system as a function of its sintering temperature…………………………………………..115 Fig. 4-22 value of (1-x)(Mg0.95Zn0.05)TiO3-x(Na0.5Nd0.5)TiO3 ceramic system as a function of its x values……………………………………………………….115 Fig. 5-1 XRD patterns of alpha alumina thin films with (a) different rf powers at a fixed substrate temperatures of 450℃ and (b) various substrate temperatures at a fixed rf power of 400 W……………………………………………………………..116 Fig. 5-2 SEM micrographs of alpha alumina thin films with (a) different rf powers at a fixed substrate temperatures of 450℃ and (b) various substrate temperatures at a fixed rf power of 400 W……………………………………………………….118 Fig. 5-3 AFM surface morphology of alpha alumina thin films with different rf powers at a fixed substrate temperatures of 450℃, (a) 200 W, rms: 10.047 nm, (b) 300 W, rms: 8.204 nm, and (c) 400 W, rms: 6.213 nm………………………………...119 Fig. 5-4 AFM surface morphology of alpha alumina thin films with various substrate temperatures at a fixed rf power of 400 W. (a) 350℃, rms: 8.650 nm, (b) 400℃, 7.287 nm, and (c) 450℃, 6.213 nm……………………………………………120 Fig. 5-5 The I-V curves of the Pt/Al2O3/Si MIS structure with (a) different rf powers at a fixed substrate temperatures of 450℃ and (b) various substrate temperatures at a fixed rf power of 400 W……………………………………………………….121 Fig. 5-6 The dissipation factor of alpha alumina thin films with (a) different rf powers at a fixed substrate temperatures of 450℃ and (b) various substrate temperatures at a fixed rf power of 400 W……………………………………………………….122 Fig. 5-7 Thickness of alpha alumina thin films with (a) different rf powers at a fixed substrate temperatures of 450℃ and (b) various substrate temperatures at a rf power of 400 W………………………………………………………………..123 Fig. 5-8 The C-V curves (f = 10 MHz) of the Pt/Al2O3/Si MIS structure at a fixed substrate temperatures of 450℃ and a fixed rf power of 400 W………………………..124 Fig. 5-9 Dielectric constant of alpha alumina thin films with (a) different rf powers at a fixed substrate temperatures of 450℃ and (b) various substrate temperatures at a fixed rf power of 400 W……………………………………………………….125 Fig. 6-1 Basic structures of SIR (a) Quarter-wavelength type and (b) Half-wavelength type………………………………………………………..126 Fig. 6-2 Electrical parameters of elementary SIR………………………………………..126 Fig. 6-3 Resonance condition of SIR…………………………………………………….127 Fig. 6-4 Equivalent circuit of a feed structure………………………………………...127 Fig. 6-5 Layout of the microstrip bandpass filter with capacitive loads…………………128 Fig. 6-6 Simulated frequency responses for (a) AT and (b) 96MZST ceramic substrates.129 Fig. 6-7 Measured frequency responses for (a) AT and (b) 96MZST ceramic substrates..130 Fig. 6-8 Photograph of the filter prototypes: (a) AT and (b) 96MZST ceramic substrates……………………………………………………………………..131