Comparative study of electro‐thermal characteristics of 4500 V diffusion‐CS IGBT and buried‐CS IGBT

Abstract

Abstract This article compares the major characteristics of the Insulated Gate Bipolar Transistor with Diffusion Carrier Stored (CS) layer (DCS‐IGBT) and the Insulated Gate Bipolar Transistor with the Buried CS layer (BCS‐IGBT). In the DCS‐IGBT, an N‐well is formed by phosphorus ion implantation and drive‐in for creating the CS layer, whereas, in the BCS‐IGBT, the CS layer is formed by forming a buried layer implant followed by growing an epitaxial layer. It is found that, at blocking voltage of 5700 V, the BCS‐IGBT achieves an on‐state voltage, VCEsat, of 2.04 V at a current density of 75 A/cm2 for a gate voltage of 15 V. Under the same conditions, the on‐state voltage of DCS‐IGBT is 2.32 V, which is about 0.28 V higher than that of the BCS‐IGBT at room temperature. Additionally, at 125°C the VCEsat of the DCS‐IGBT is about 0.38 V higher than that of the BCS‐IGBT. TCAD simulations are employed to investigate and explain the electro‐thermal characteristics differences between these two devices. Furthermore, the ruggedness of the both devices are studied and compared. It is found that the DCS‐IGBT is more rugged than BCS‐IGBT, for example the short‐circuit withstanding time (SCWT) of DCS‐IGBT and BCS‐IGBT are 22 and 16 µs, respectively.

Keywords

• buried layers
• insulated gate bipolar transistors
• ion implantation
• phosphorus
• semiconductor device models
• technology CAD (electronics)