一种新型的双极功率器件—BST

A New Bipolar Power Device-BST

针对常规双极功率晶体管（ＢＰＴ）中存在的高频、高电流增益和高ＣＥ击穿电压间的固有矛盾，基于一新工艺提出了一种新型的双极功率器件──ＢＳＴ（ＢａｓｅＳｈｉｅｌｄｉｎｇＴｒａｎｓｉｓｔｏｒ）结构。分析了ＢＳＴ夹断后的两维电场解析解，可知深Ｐ＋多晶硅基区的引入对有源Ｐ基区产生明显的电场屏蔽效应，该基区屏蔽效应随Ｐ＋基区深入Ｎ－区中的深度Ｌ的增加以及相邻Ｐ＋基区间距２Ｄ的减小而增强。正是这种基区屏蔽效应，使得ＢＳＴ的特征频率ｆＴ、电流增益ｈｆｅ和ＣＥ击穿电压ＢＶｃｅ０都较常规ＢＰＴ大为提高，较好地解决了常规ＢＰＴ中存在的主要矛盾。实验验证了理论分析的结果。

In order to solve the intrinsic contradictions among the fT, hfe and BVce0 of conventional bipolar power transistor (BPT), a new bipolar power de vice-BST (Base Shielding Transistor) based on a new process is proposed in this paper. The operating mechanism of BST is described and its pinch off model is set up. An analytic solution of two-dimensional electric field is obtained by solving two-dimensional poisson equation after the BST is pinched off. According to the model, the deep P+- polycrystalline-silicon base region electrostatically shields the active P base region. The intensity of the base shielding effect increases with the increase of L and decrease of D. Compared with the conventional BPT, hfe, fT and BVce0 of the BST are much greater because of the base shielding effect. The BST successfully solves the main contradictions which exist in the conventional BPT. These results have been verified by experiment.