Papers by Author: Martin Kuball

Abstract: This paper presents a comparative analysis of 1200 V Silicon Carbide (SiC) MOSFETs characterized at bare die level and in TO-247 packaging. Static parameters including transconductance (g_m), drain leakage current (I_DS-OFF), output (I_DS-V_DS) and transfer characteristics (I_DS-V_GS), gate threshold voltage (V_GS(th)) and on-state resistance (R_DS(on)) are examined. Results show that the TO-247 package introduces parasitic resistance/inductance and higher thermal impedance, leading to disrupted g_m, though lower leakage I_DS-OFF, shifted V_GS(th), and elevated R_DS(on). The study quantifies the discrepancy between intrinsic die behavior and packaged device performance, underscoring the need to de-embed packaging effects for accurate device modelling and optimization.

Abstract: Recent work on the thermal and electrical challenges in realizing AlGaN/GaN microwave heterojunction field effect transistors grown on SiC substrates is discussed. Raman thermography has been used to directly measure the self-heating induced lattice temperature rise with dramatically improved resolution and accuracy compared to traditional infrared techniques. It is demonstrated that defects in the SiC substrate can influence the temperature distribution within the active device with potential consequences for reliability. Microwave devices require an insulating GaN substrate material for device isolation. It is shown that the net deep level acceptor concentration has to be accurately controlled to suppress short-channel effects and to achieve radio frequency power efficient operation.