Evaluation of accuracy of SiC-JFET macromodel

Abstract

In the paper, the results of experimental verification of the macromodel of UJN1208K JFET transistor made of silicon carbide fabricated by United Silicon Carbide, are presented. The macromodel form dedicated for PSPICE program is available on the manufacturer's website. The accuracy of the macromodel have been evaluated by comparison of selected calculated and measured static characteristics and C-V characteristics of the considered transistor. The influence of ambient temperature on the characteristics of the transistor has been evaluated, as well.

Modelling of Dynamic Properties of Silicon Carbide Junction Field-Effect Transistors (JFETs)

“…These capacitances constitute an appropriate combination of transistor junction capacitances. Capacitances Ciss, Coss and Crss are expressed with the following formulas [10]: As seen, for small V GS and V GD bias voltages of around 1 V a good agreement between the simulation and measurement results can be observed. However, quantitative and qualitative discrepancies reaching even one order of magnitude are observed in the case of C GS (V) and C GD (V) characteristics (Figure 2a The manufacturers of the JFET transistors present in datasheets [25] the characteristics of capacitances C iss , C oss and C rss as a function of specified terminal voltages.…”

“…These capacitances constitute an appropriate combination of transistor junction capacitances. Capacitances C iss , C oss and C rss are expressed with the following formulas [10]:…”

“…The dynamic properties of a JFET depend on, among others, the values of diffusion and junction capacitances of the internal gate-source and gate-drain p-n junctions of the transistor [8][9][10]. Both capacitances are functions of the terminal voltage applied and play an important role in the forward and the reverse polarization of the device.…”

“…Both capacitances are functions of the terminal voltage applied and play an important role in the forward and the reverse polarization of the device. On the other hand, the dynamic properties of JFETs are characterized by parasitic capacitances resulting from the non-zero size of the transistor structure [8][9][10][11].…”

“…Recently, a successful attempt at modeling the static characteristics and parameters of SiC-JFETs using the S-H model have been reported [19,20]. On the other hand, selected aspects of modelling dynamic characteristics of JFETs were presented in [8][9][10][21][22][23][24].…”