Demonstration and Analysis of Ultrahigh Forward Current Density Diamond Diodes
Harshad Surdi, Franz A. Koeck, Mohammad Faizan Ahmad, T. J. Thornton, R. J. Nemanich, Stephen M. Goodnick
Abstract
A diamond Schottky p-i-n diode (SPIND) with the highest reported current density to date of ~116 kA/cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> is demonstrated, carrying a total current of ~1.32 A through a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$50-\mu \text {m}$ </tex-math></inline-formula> wide pseudo-vertical diode structure. The diamond SPIND also provides a maximum power handling capacity of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${1.85}~ \text {MW/c}\text {m}^{{2}}$ </tex-math></inline-formula> and a low specific ON-resistance <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}_{ \mathrm{ON}}S$ </tex-math></inline-formula> of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${0.05}~ \text {m}\Omega \cdot \text {cm}^{{{2}}}$ </tex-math></inline-formula> at a forward bias of ~16 V. The diamond Schottky p-i-n (SPIN) diode also shows excellent rectification characteristics with a current ON– OFF-ratio of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\sim {6} \times {10}^{{12}}$ </tex-math></inline-formula> . An analytical model including thermionic emission and space charge limited (SCL) current is presented together with Silvaco ATLAS Technology Computer Aided Design (TCAD) simulations to accurately reproduce the experimental <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${J}$ </tex-math></inline-formula> – <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}$ </tex-math></inline-formula> characteristics using multiple single-trap levels and other physical models emulating a real device. Theoretical calculations from the analytical model show that further improvement in the device turn on voltage and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${R}_{ \mathrm{ON}}{S}$ </tex-math></inline-formula> can be achieved by reducing the defect density and contact resistance in order to approach the ultimate performance in the Mott–Gurney SCL current regime.