Luận án: Thiết kế, chế tạo cảm biến áp suất SAW dùng Nitrure Nhôm (AlN)

Introduction

1.1. Acoustic wave devices

1.1.1. Thickness Shear Mode (TSM) resonator

1.1.2. Surface Acoustic Wave Device

1.1.2.1. SAW excitation and detection

1.1.2.2. SAW perturbation mechanisms

1.1.3. Acoustic Plate Mode (APM) devices

1.1.4. Flexural Plate Wave (FPW) or Lamb wave device

1.1.5. Comparation between four sensors

1.2. SAW sensor and the application pressure sensor in this research

1.2.1. SAW pressure sensor with one port IDT

1.2.2. SAW pressure sensor with two ports IDT

1.3. Aluminum Nitride (AlN) and its applications in SAW devices

1.3.1. Piezoelectric materials and the choice of AlN

1.3.2. General Information of AlN

1.4. Modelling SAW devices

1.4.1. Why Equivalent Circuit model is chosen?

1.4.2. The Finite Element Model (FEM)

1.5. Micromachining process, the choice of surface micromachining

2. Chapter 2: SAW PARAMETERS ANALYSIS AND EQUIVALENT CIRCUIT OF SAW DELAY LINE

2.1. Calculation of SAW properties

2.1.1. Wave velocity, coupling factor in AlN/Si structure

2.1.2. Wave velocity, coupling factor in AlN/SiO2/Si structure

2.1.3. Wave velocity, coupling factor in AlN/Mo/Si structure

2.2. Equivalent circuit for SAW delay line based on Mason model

2.2.1. Equivalent circuit for IDT including N periodic sections

2.2.2. Equivalent circuit for propagation path

2.2.3. Equivalent circuit for SAW delay line

2.3. Equivalent Circuit for IDT Based On The Coupling-Of-Mode Theory

2.3.1. COM equation for particle velocities

2.3.2. Equivalent circuit for IDT based on com theory

2.3.3. Equivalent circuit for propagation path based on com theory

2.3.4. Equivalent circuit for SAW delay line based on COM theory

2.4. Comparison of Equivalent circuit of SAW device based on Mason model and COM thoery

3. Chapter 3: DESIGN OF SAW PRESSURE SENSOR DEVICES

3.1. Temperature compensated structure for SAW device

3.1.1. Temperature dependence of Si, SiO2, AlN properties

3.1.2. Temperature Coefficient of Frequency (TCF) and temperature compensated structure for SAW sensor

3.2. Pressure dependence of frequency and phase in saw delay line

3.2.1. Mechanical analysis of membrane under pressure

3.2.2. Pressure-dependence of frequency by pressure dependence of AlN elastic properties

3.2.3. Pressure-dependence of frequency by delay line

3.2.4. Pressure-dependence of phase shift

4. Chapter 4: FABRICATION PROCESS

4.1. Trench, counter masque, hole, and PSG layers

4.2. Metal AlCu and polyimide layers

4.3. Creating the stop wall of etching SiO2- Trench

4.4. Non-selective epitaxy

4.5. COUNTER MASK lithography, etching Si and CMP process

4.6. HF Etching of the sacrificial layer

4.7. Depositing AlN as the piezoelectric layer and its properties

4.7.1. Influence of substrate roughness on crytal quality of AlN

4.7.2. Dependence of FWHM of AlN on AlN thickness

4.7.3. Dependence of FWHM of AlN on using bottom MO layer

4.7.4. AlN at high temperature

4.8. Metal layer AlCu for IDT and probes

4.9. Polyimide as absorber

5. Chapter 5: CHARACTERIZATION OF SAW DEVICE

5.1. The Square Resistance: Van Der Pauw

5.2. Isolation and continuity

5.3. Measuring under etching

5.4. Mask for parametric test

5.5. Propagation losses measurement

5.6. Piezoelectric coupling factor extraction

5.7. Comparison between experiment and simulation

5.8. Effect of Mo layer on performance of AlN/Si SAW device

5.9. Effect of thin Polyimide film

5.10. Device under pressure

CONCLUSION and PERSPECTIVE

List of publication paper

Appendix A: Properties of Si, SiO2, AlN and Mo

Appendix B: Development of calculation for equivalent circuit of SAW device

Appendix C: Equipments used to control each fabrication step and to characterise device

C.1. SCANNING ELECTRON MICROSCOPE (SEM)

C.2. VEECO PROFILING SYSTEM

C.3. ATOMIC FORCE MICROGRAPH (AFM)

C.4. X-RAY DIFFRACTION (XRD) SYSTEM

C.5. SURFACE PROFILER TENCOR P-11

C.6. FLEXUS F2320 DUAL WAVELENGTH STRESS MEASUREMENT SYSTEM

List of tables

List of figures