Reaseach On Effects Of Boron-doped On The Structure In Accelerometer

The accelerometer is an inertial sensor device to measure the inertial parameter,such as the force, inclination angle, external shock and vibration of the structure. In thispaper, the accelerometer is based on bulk silicon manufacturing process. Although thisprocess is becoming a mature technology, it is known that this manufacturingtechnology still has a lot of shortcomings and deficiencies.Micro machining processes often change the electrical properties of materials bydoping technology to become the semiconductor device for electronic equipment. Theboron-doped process is the most widely used in doping technique; however, the boronatoms instead of the silicon atoms will change the material properties on the structure.Such as the internal stress, doping concentration, and crystal defects, would cause thebulking phenomenon and change the stiffness of structure for the micro silicon sensor.These two effects are directly related to the input and output of the accelerometer andare the major source of error in inertial sensor. This paper studies the impact of borondoping on the mechanical properties of the sensor core structure. The main contents are:1. For the boron doping process of the silicon material, study the volume shrinkage.The boron-doped distribution will be known by EDP etch-stop process and then it isused to simulate the shrinkage strain and Young’s modulus variation.2. Analysis the bulking theory of the accelerometer structure, establish a mechanicalmodel to obtain the theoretical formulas. And the bulking deformation will be getby the numerical.3. Analysis the stiffness expression of the boron-doped silicon beam and compared itwith the single crystal silicon beam. Calculating the stiffness range in the size of thesupport beam.4. Simulate the bulking phenomenon and the stiffness of the accelerometer structureby finite element analysis software, COMSOL MULTIPHYSIS and ANSYS. Andthen the simulation results and numerical solutions are compared with theexperimental results and considered correct.