The trade-off between the breakdown performance and the Kirk effect has been evaluated and compared among conventional bipolar transistors and resurfed lateral bipolar transistors. It was demonstrated that the traditional conflict of differing requirements on W-c and N-c by the breakdown performance and the Kirk effect can be eased by incorporating the resurf principle. Comparative studies have been carried out between the optimized devices with breakdown voltages from 20 to 40 V. It is shown that for an identical breakdown voltage, the high-current-level performance of the resurfed devices can be significantly improved by incorporating a gradually doped collector region. This further leads to a significant increase in the cut-off frequency without degrading the breakdown performance.