Temperature-Dependent ESD Breakdown in AlGaN/GaN HEMTs With Carbon-Doped Buffer

This work investigates the temperature-dependent electrostatic discharge (ESD) behavior of AlGaN/GaN HEMTs using a transmission line pulsing system, which becomes relevant under practical system-level scenario. Two devices with different carbon doping concentrations in the buffer are tested. It is observed that in low-carbon-doped devices, breakdown/failure voltage (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {BD}}$ </tex-math></inline-formula>) decreases with increasing temperature, while in the high-carbon-doped devices, <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {BD}}$ </tex-math></inline-formula> shows a weak temperature dependence. A unique behavior is identified where the location of the channel electric field peak determines the temperature-dependent ESD breakdown behavior of the GaN HEMT devices. When the channel electric field peaks at the field plate edge (FPE), <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}_{\text {BD}}$ </tex-math></inline-formula> shows a negative temperature coefficient, whereas it shows a weaker temperature dependence when the channel electric field shifts to the drain edge (DE). In situ and on-the-fly electrical and optical characterizations, such as electroluminescence (EL) microscopy and micro-Raman spectroscopy, and TCAD computations are performed to get deeper insights into the failure mechanisms. Postfailure analysis using scanning electron microscopy and focused ion beam (FIB) microscopy is also carried out to probe material-level implications on the failure of LC and HC devices.