mCube says it has the world's smallest three-axis MEMS accelerometer and the only monolithic single-chip version with integrated MEMS and ASIC on the same die. The device is shown here in a 3x3 mm package but is also available in a 2x2 mm package.
The ASIC is first grown on the bottom, then the MEMS mechanical elements are fabricated above and connected with tiny 3 micron vias after which the MEMS element is hermetically sealed with a silicon cap.
Further Reading
