Low pressure chemical vapor deposition of silicon nitride and silicon oxynitride layers and their application in optical waveguide based chemical sens [...] / Ahmed Tamim. 2007
Inhalt
- cover English
- aknow-
- Abstract
- Deutsch Abstract
- PhD
- 1.1 Silicon technology
- 1.2 Low pressure chemical vapor deposition (LPCVD)
- 1.3 Silicon nitride (Si3N4)
- 1.4 Silicon oxynitride (SiON)
- 1.5 Optical waveguides
- 1.6 Chemical sensors
- 1.6.1 Background
- 1.6.2 Historical Perspective of chemical sensors
- 1.6.3 Applications of chemical sensors
- 1.7 Optical waveguide based chemical sensors
- 1.8 Ammonia sensors
- 2.1 Introduction
- 2.2 Waveguide design
- 2.3 Design of Mach–Zehnder interferometer (MZI)
- 2.4 The heater design
- 3.1 Introduction
- 3.2 Description of LPCVD process
- 3.3 Measuring of layer thickness and refractive index by ellipsometer
- 3.4 Preparation of the silicon wafers
- 3.5 Deposition process
- 3.5.1 Silicon nitride (Si3N4) deposition
- 3.5.1.1 Deposition of Si3N4 at 740 °C
- 3.5.1.2 Deposition of Si3N4 at 760 °C
- 3.5.1.3 Deposition of Si3N4 at 780 °C
- 3.5.1.4 Temperature optimization
- 3.5.2 Silicon oxynitride (SiON) deposition
- 4.1 Introduction
- 4.2 Sensor fabrication
- To build a sensor, sensitive material had to be selected that changes its refractive index in response to the presence of a targeted chemical substance, such as ammonia in ambient air. One of the choices was a thin film of polymer doped with an appropriate indicator dye. Dye-doped polymers are traditionally used in optical chemical sensors, or optodes, based on a change in optical absorption. In our case, however, the sensitive optical parameter to be measured was not the absorbance but the refract
- 4.3 Experimental results