Design consideration of device dimension and sturcture of power HBT transisor

In this paper several sub-cell and unit-cell power heterojunction bipolar transistor were fabricated and the impact of device dimension and structure on the device characteristic of sub-cell and unit-cell power HBT Transistor is analyzed and discussed. It was found that: for the sub-cell HBT with different dimension a larger emitter size means smaller RF gain. When the sub-cells were used to form unit-cells, the unit-cell, which was formed by the larger sub-cell HBT, has the smaller loss of RF gain, the smaller layout area and the higher intrinsic stability.