• Lophitis, Neophytos
• Trajkovic, Tatjana
• Udrea, Florin
• Perkins, Samuel
• Antoniou, Marina
• Tiwari, Amit K.

Abstract

<p>In this paper, we propose the use of a retrograde doping profile for the p-well for ultrahigh voltage (&gt;uexcl;10 kV) SiC IGBTs. We show that the retrograde p-well effectively addresses the punchthrough issue, whereas offering a robust control over the gate threshold voltage. Both the punchthrough elimination and the gate threshold voltage control are crucial to high-voltage vertical IGBT architectures and are determined by the limits on the doping concentration and the depth that a conventional p-well implant can have. Without any punchthrough, a 10-kV SiC IGBT consisting of retrograde p-well yields gate threshold voltages in the range of 6-7 V with a gate oxide thickness of 100 nm. Gate oxide thickness is typically restricted to 50-60 nm in SiC IGBTs if a conventional p-well with 110^{17} cm^-3 is utilized. We further show that the optimized retrograde p-well offers the most optimum switching performance. We propose that such an effective retrograde p-well, which requires low-energy shallow implants and thus key to minimize processing challenges and device development cost, is highly promising for the ultrahigh-voltage (&gt;10 kV) SiC IGBT technology.</p>

Topics

• impedance spectroscopy