SOI Novel Structure Fabrication And Investigation Of Suspended Type Thin Film Resonator Based On SOI

SOI (Silicon-on-Insulator) technology develops rapidly with development of low voltage/power circuits and has been considered as the technology of the future microelectronics. It can break through many restriction of traditional Si device and be widely used in space, photoelectron and MEMS domain. According to the National Project 973 and the National Science Foundation Project of China, we have developed some innovation work, which is resolving self-heating in traditional SOI device and fabricating new structure SOI material. The words in this thesis focus on 3 aspects: The first one is to fabricate new structure SOI mateial which is using AlN as buried insultor replacing traditional SiO₂ insulator by Smart-Cut technology. The sceond one is to prepare SOG (Silicon-on-Glass) new SOI structure by hydrophilic fusion bonding and Smart-Cut technology for flat panel display application. The third one is fabricate novel suspended type thin film resonator using the SOI technology. We have taken the lead in bringing forward a novel Silicon-on-AlN(SOAN) structure SOI material in order to resolve self-heating effect of traditional SOI device. Self-heating in SOI device is responsible for degradation in mobility, threshold voltage, subthredhold swing, leakage, etc. since self-heating is mainly due to the poor thermal conductivity of the buried oxide, an elegant solution is to replace the BOX with buried other dielectric, which can offers much higher thermal conductivity. AlN has been investigated owing to its attractive properties including excellent the thermal conductivity, thermal stability, high electrical resistance and a coefficient of thermal expansion close to that of the silicon, and so on. Thereby, using AlN replacing SiO2 as buried insulator can radically improve the self-heating in traditional SOI device which can greatly increase the application scope of SOI material in high temperature, high power integrate circuit. In the paper, AlN films are prepared by Ion Beam-Assisted Deposition (IBAD) system. Composition, chemical nature and structure of the films have been investigated. The surface roughness RMS values of the prepared AlN thin film is about 0.44nm that can meet the need of direct bonding without polishing step. The effective electric permittivity of AlN film is 8.74. According to the results of calculation and characterization, we can conclude that the dielectric properties of the prepared AlN thin films are good enough and can be safely used as insulators for the application in SOI material. Smart-Cut technology is used to prepare SOAN (Silicon-on-AlN) wafer. TEM characterization shows that the single crystal silicon layer on SOAN keeps enough outstanding crystalline quality. The bonding strengths SOAN wafer is about 8.7MPa. MEDICI software is applied to simulate the analytical electrical and thermal model on traditional SOI/CMOS and SOAN/CMOS. The temperature of trench of SOAN/CMOS compared to traditional SOI/CMOS decreases about 170K. This paper presents silicon-glass wafer-to-wafer directly bonding with hydrophilic fusion bonding technology and single crystal Si layers on glass is formed by Smart-Cut technology. Good adhesion between the wafers has been achieved as measured by tensile strength testing. The bonding strength of 4"silicon-glass wafer is about 8.7MPa. The crystalline nature and the microstructure of samples are characterized using transmission electron microscopy (TEM); the electrical properties by Hall effect measurements, four-point probe. The observed mobility of the transferred Si layer on glass is about 122cm2/V?s with a hole concentration of 1.13×1016cm-3. All characterization results show that the single crystal silicon layer by directly bonding keeps enough outstanding quality for most applications ofintegrated,transducers and flat panel display. We have fabricated the novel suspended type thin film resonator (STFR) using surface micromachining and SOI technology. We use ZnO that was deposited by Ion Beam-Assisted Deposition (IBAD) system as piezoelectricity material in STFR. We use SiO2 layer in SOI wafer as sacrifice layer that can be eroded to form cavum. This method simplifies the fabrication technics and eroding end-point can easily be controlled. The novel STFR has an effective coupling coefficient ( K e2ff) of 2.35%. The bandwidth is 16MHz.