Dual injection enhanced super junction TIGBT with narrow mesa and floating-P region

For the conventional super junction trench insulated gate bipolar transistor (SJ-TIGBT), the higher the N/P column doping concentration (N_c), the better the electrical characteristics can be obtained. However, considering the negative impact of charge imbalance of the N/P column on the breakdown voltage (BV), the value of N_c is limited, which limits the improvement of device performances. In this paper, a novel SJ-TIGBT with narrow mesa (NM) and floating-P (FP) region (NMFP-SJ-TIGBT) is proposed. The electrical characteristics of the proposed SJ-TIGBT are significantly enhanced owing to the dual injection enhancement effect provided by the NM and FP region. Moreover, for the proposed SJ device, the excellent performance obtained in the lower N_c regime alleviates the negative impact of charge imbalance of N/P column on the BV, which greatly improves its fabrication process tolerance. The simulation results show that compared to the conventional SJ-TIGBT (SJ-TIGBT-A), a SJ-TIGBT with an n-injector layer (SJ-TIGBT-B) and a SJ-TIGBT with a floating-P column under the gate (SJ-TIGBT-C), the proposed structure demonstrates a significantly lower and almost constant on-state voltage drop (V_ceon). At a collector current density of 100 A/cm² and N_c of 1 × 10¹⁵ cm⁻³, the V_ceon of the proposed SJ-TIGBT is 74.9%, 41.1% and 26.1% lower than that of the SJ-TIGBT-A, SJ-TIGBT-B and SJ-TIGBT-C, respectively. With the same V_ceon of 1.05 V and N_c of 1 × 10¹⁵ cm⁻³, the turn-off loss of the proposed SJ-TIGBT is only 6.44 mJ/cm², which is 73.7% and 35.4% lower than that of SJ-TIGBT-B and SJ-TIGBT-C, respectively.