Theory Analysis And Experiment Research Of Low Temperature Si/InP Wafer Bonding Technology

The research work of this thesis is carried out on the basis of The National Basic Research Program of China (No.2003CB314900) for which professor Ren Xiaomin is responsible as a chief scientist and the project of the National Natural Science Foundation of China (No: 60576018) .Si is one of the maturest micro-electronics materials and popularly applied in electronics circuit region. However, the character of indirect band gap determines its low luminescent efficiency. The active region of long wavelength lasers and photo-detectors are generally fabricated by InP serial materials. The integration of Si/InP is an effective approach to integtate electronics circuits with laser or photodetector.The integration of two different materials can be achieved by two approaches: heteroepitaxial grown technology and wafer bonding technology. The Lattice constant mismatch of Si and InP is up to 8．1%, so conventional heteroepitaxial grown technology will introduce evident misfit dislocation. On the contrary, wafer bonding technology possesses many advantages which can be utilized to obtain good quality of Si/InP heterojuction. Acording to the annealing temperature, wafer bonding techno-logy can be classifyied as high-temperature wafer bonding and low-temperature wafer bonding.High-temperature thermal treatment in bonding process will result in large thermal stress, which leads to dislocations in the interface of Si/InP and degradation of devices. Then, the other one, low-temperature bonding technology, becomes an effective approach to implement Si/InP heterojuction. In general, low-temperature bonding technology needs more strict conditions and more complicated equipments with high cost. Howerver, we develop a low-cost and efficient low-temperature technology which is used to bond the Si/InP wfers at 270℃.In this thesis, theory analysis and experiment research about low temperature Si/InP wafer bonding are systematically carried our. The work can be summarized as follows: 1．The principle, advantages and application of direct wafer bonding is discussed; The bonding interface characters such as interface layer and bonding strength are investigated; The origin of three kinds of misfit dislocation is analyzed.2．The I/V characters of Si/InP bonded wafers are theoretically researched, using the model of two Schottky diodes back-to-back, and taking into account the resistance affection, current-voltage relation is abtained.3．The relation of thermal stress arising in thermal treatment with wafer thickness and Si/InP material characters is theory researched, because it greatly impacts the quality of wafer bonding. The result show that the thermal stress can be reduced by thinning the wafers bonded.4．The applied load influence to the contact area is researched, based on the DMT theory on the contact and adhesion between elastic bodies with a random distribution of wafer surface considered. The relation of bonding area and applied load is obtained.5．The bonding clamp performances directly affect the bonding quality. According to the bonding characters, the bonding clamp which is successfully designed is easy to operate and has some innovation. The elastic component can be repeatedly used at 500℃. The pressure component can the pressure on Si/InP wafers uniform.6．Convention wafer bonding fabrication process is discussed. Based on the equipment and facility in our laboratory, I take part in the fabrication process developing of low temperature Si/InP wafer bonding. With the help of Dr. Wang Wenjuan and Dr. Song Hailan, I completed Si/InP wafer bonding.7．I-V curves of Si/InP,GaAs/InP,Si/Si are measured and the influence of wafer bonding on device electrical character is discussed. Using the model of two Schottky diodes back-to-back and measured result, the I-V curves is analyzed.