A new trench base-shielded bipolar transistor

In this paper, a new power bipolar transistor structure called the trench base-shielded bipolar transistor (TBSBT) Is proposed and experimentally demonstrated. This structure incorporates deep p/sup +/ poly-Si trenches into the base of a conventional bipolar transistor. With the base shielded effectively by the p/sup +/ trenches, the base of the TBSBT can be made very narrow to achieve high current gain h/sub FE/ and high cut-off frequency f/sub T/ without compromising on the breakdown voltage. Experimental results show that the on-state anti switching characteristics of the TBSBT are significantly better than those of the existing power bipolar transistors.