On the Assessment of Temperature Dependence of 10 - 20 kV 4H-SiC IGBTs Using TCAD

Abstract

This paper addresses and evaluates the temperature dependence performance of silicon carbide (4H-SiC) based insulated gate bipolar transistors (IGBTs) using two dimensional numerical computer aided design tool (i.e., Atlas TCAD from Silvaco). Using identical set of device physical parameters (doping, thicknesses), simulated structure was first caliberated with the experimental data. A minority carrier life time in the drift layer of 1.0 – 1.6 µs and contact resistivity of 0.5 - 1.0 x 10-4 Ω-cm2 produces a close match with the experimental device. A set of n type IGBT structures were then numerically simulated to extract the conduction losses for various blocking voltage classes. An on-resistance first decays with temperature (i.e., increased in ionization level, and increase in minority carrier life time), stays nearly constant with further increase in the temperature (may be all carriers are now fully ionized and increase in carrier life time is compensated with decrease in the carrier mobility) and finally increases linearly with temperature (>450 oC) due to decrease in the carrier mobility. Compared with Si based IGBTs, numerical simulation predicts lower VCEON and RON values for 4H-SiC based IGBTs for higher voltage classes and hence potential for achieving smaller conduction losses for SiC based IGBTs.

Numerical analysis and thermal fatigue life prediction of solder layer in a SiC-IGBT power module

“…Silicon carbide (SiC) material has better material properties has shown a broader prospect in electronic packaging, which is attributed to its high strength Si-C bonding [4]. Silicon carbide insulated gate bipolar transistors (SiC-IGBTs) are characterized by higher breakdown voltage, fast operating frequency, high power speed and high current density [5], therefore, they have better heat resistance than conventional Si-IGBTs and a wide potential application. At the same time, the highest operating junction temperature of the SiC-IGBT can be as high as 175 °C, which allows the device itself be more adaptable to higher power density [6].…”

4H-SiC trench IGBT with lower on-state voltage drop

“…In past several years, some high-voltage 4H-SiC IGBTs with the breakdown voltage in range from 10 to 22 KV have been reported [12][13][14][15][16][17][18][19][20][21][22][23][24]. However, these works mostly focus on planar gate 4H-SiC IGBT and a few studies about 4H-SiC trench IGBT [12,15,22].…”

On the Evaluation of Gate Dielectrics for 4H-SiC Based Power MOSFETs

“…Compared to conventional Si material (used today for standard CMOS and for variety of high power applications ranging from 25 to 125 ∘ C), silicon carbide is a wide bandgap material (i.e., 3 times than that of Si) having larger thermal conductivity values (i.e., 3 times than that of Si) and larger breakdown field strength (i.e., 10 times than that of Si) and offers larger carrier saturation velocity (i.e., 2 times than that of Si). Because of these unique features, SiC material is well blessed for high power devices [10][11][12][13][14][15][16][17][18][19][20] for applications ranging from −75 up to 550 ∘ C [4].…”

“…Silicon carbide based semiconductor devices such as Schottky diodes [3], junction field effect transistors (JFETs) [8,9], bipolar junction transistors (BJTs) [4][5][6][7], metal oxide semiconductor field effect transistors (MOSFETs) [11][12][13][14][15], insulated gate field effect transistors (IGBTs) [16][17][18][19][20], and integrated gate commutated thyristors (IGCTs) [10] are explored today as potential candidates to meet the growing demand from the point of view of power system compactness that offer increased power density and simultaneously reduced overall system losses. While significant progress at material and device level research has been made and resulted in commercialization of some of these devices, reliability concern has been raised either in the passivation process for BJTs/JFETs [7,8] or in gate dielectric process for MOSFETs/IGBTs [11][12][13][14][15][16][17][18][19][20] that may present one limiting factor for reliable performance of these devices in real applications. Note that most of these devices use silicon dioxide (SiO 2 ) as a passivation layer protecting the device surface or as gate dielectric process.…”