600V Insulated Gate Bipolar Transistor Design for Improving Breakdown Voltage in Trench Floating P-Well Charge Storage Layer Gate Bipolar Transistor

Insulated Gate Bipolar Transistors (IGBT) [1][2] play a crucial role in medium to high voltage switching applications and have undergone extensive development and improvement in their basic structures. Various technologies have been continually proposed to address the trade-off between turn-off losses and on-state voltage, including field stop IGBTs, Carrier Stored Trench Gate Bipolar Transistors (CSTBT) [3], and Gate Injection Enhanced Transistors (IEGT) [4].As IGBTs need to withstand high currents during conduction, an increase in on-state voltage results in higher power consumption, impacting not only energy efficiency but also posing challenges in terms of heat dissipation. Conventional CSTBT optimize carrier distribution in the drift region by adding a carrier storage layer beneath the P-Well, thereby increasing the on-state voltage. However, CSTBT are highly sensitive to the doping concentration of the carrier storage layer. An increase in doping concentration narrows the depletion region in the drift region under high-voltage conditions, simultaneously raising the electric field at the bottom of the gate, thus reducing the breakdown voltage of the device. To address this issue, this paper proposes a Carrier Stored Trench Gate Bipolar Transistor with a floating P-column. In this new structure, the breakdown mechanism of the superjunction[5] is influenced by charge balance rather than being constrained by the P-Well and the width of the depletion region in the drift region. This effectively enhances the breakdown voltage while maintaining a favorable on-state voltage for CSTBT. The study employs the simulation software ISE-TCAD for the analysis and investigation of various characteristics, comparing the proposed structure with traditional trench gate IGBT.