Demonstration of 1.2-kV Rated Novel Power Poly-Si/4H-SiC Heterojunction Diode With Record Low Forward Voltage Drop

The forward voltage drop (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {F}}$ </tex-math></inline-formula>) is one of the most critical parameters of power diodes, determining the power consumption and specific area performance. In this article, a novel 1.2-kV rated 4H-silicon carbide (SiC) power heterojunction diode (HJD) with the n-type ion-implanted polycrystalline silicon (Poly-Si) anode is proposed and experimentally demonstrated for the first time, featuring a record low <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {F}}$ </tex-math></inline-formula> of 1.080 V at the 2.5-A/mm2 forward current density (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${J}_{\text {F}}$ </tex-math></inline-formula>), which is 25% lower than reported conventional 4H-SiC power diodes with the Ti metal anode. The heterojunction barrier height is extracted to an ultralow 0.804 eV, accounting for the remarkable <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {F}}$ </tex-math></inline-formula> decrease. The introduction and optimization of the p-type shielding region enables the avalanche breakdown voltage above 1500 V. The increase in the reverse current density (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${J}_{\text {R}}$ </tex-math></inline-formula>) with lowering barrier height is also suppressed even at high temperature (T). <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${J}_{\text {R}}$ </tex-math></inline-formula> at the 800-V cathode voltage is decreased to be 1.47 and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$231~\mu $ </tex-math></inline-formula>A/mm2 at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${T} =298$ </tex-math></inline-formula> and 423 K, respectively. The almost zero reverse recovery and perfect dynamic performance are demonstrated by the double-pulsed switching test platform. The experimental investigations as well as the developed fully compatible fabrication process show the great potential of the proposed HJD as the next-generation low-loss device.