MEMS piezoresistive pressure sensors are widely used in automobile, aerospace and petrochemical industries due to their small size, simple reading circuit, batch fabrication capability and low price. However, there are two drawbacks for the traditional structural silicon substrate sensors. One is from the trade-off between sensitivity and linearity which are difficult to be improved simultaneously for the traditional flat membrane. Another is from the leakage current above 125 C temperature across the p-n junction, which will significant degrade the performance. XI TABLE OF CONTENTS