一种背面深槽填充P型多晶硅RC-IGBT

提出了一种新型RC-IGBT,在背面阳极处设置了填充重掺杂P型多晶硅的深槽和FOC浮空电极。器件正向导通时,利用重掺杂P型多晶硅与N型衬底的接触电势差,将槽间的N型衬底部分耗尽,增强了阳极PN结的短路电阻,在较短背面阳极尺寸的条件下实现了RC-IGBT在开启过程中不出现电压折回现象。在器件反向开启过程中,空穴电流经过FOC浮空电极流入P型多晶硅,降低了多晶硅与N型衬底之间的势垒,提高了反向二极管的开启速度,降低了开启过程中二极管的过充电压。仿真结果表明,提出的新型RC-IGBT完全消除了电压折回现象,反向电流的均匀性得到了提高。相比于传统RC-IGBT,该新型RC-IGBT的元胞背面尺寸减小了88.89%,关断损耗降低了26.37%,反并联二极管的反向恢复电荷降低了13.12%。

A RC-IGBT with Backside-Trench Filled with P-Type Poly Silicon

A novel RC-IGBT with FOC floating electrode and backside-trench which was filled with heavily doped P-type poly silicon at the anode was proposed. When the device was turned on, the short-circuit resistance of the anode PN junction was enhanced with the contact potential difference between the P-type poly silicon and the N-type substrate. When the device was in the reverse conducting state, the hole current flowed into the P-type poly silicon through the FOC floating electrode which reduced the potential difference between the P-type poly silicon and the N-type substrate, thereby having increased the turn-on speed and lowering the overshot voltage. Numerical simulations showed that the snapback phenomenon was eliminated completely, and the uniformity of the reverse current was improved. The back-side cell size of the proposed RC-IGBT was reduced by 88.89%, the turn-off loss was reduced by 26.37%, and the reverse recovery charge of anti-parallel diode was reduced by 13.12% compared with that of the conventional RC-IGBT.