The Experimental Study Of4H-SiC Power BJT

Silicon Carbide （SiC） has a broad prospect for the study and commercial becauseof its superior material properties suitable for high power, high temperature andanti irradiation applications. As an important power device, bipolar junctiontransistor （BJT） has been a subject of more and more interest in recent years, sincepower BJT based on4H-SiC could eliminate the drawbacks of Si based power BJTand the gate-oxide quality of MOSFET based on4H-SiC.For the purpose of4H-SiC BJT device experimental study, this paper containsthe following:First, the double base structure is selected according the comparison of manyliteratures. The best structure parameter, which is obtained by simulation software,is used as a target for the growth of epitaxial growth. Then the practical structureparameter is simulated again, the results show that the common emitter DC gain is120, the open base breakdown voltage is450V and the specific on resistance is5.4mΩ·cm².Then, the key fabrication of4H-SiC BJT is studied by the special experimental,including ICP etching and P-type ohmic contact. Finally, we achieve the etchingrate of3.47nm/s and etching precision of30nm from the optimized parameters ofICP etching system. Meanwhile, the suitable metal layer for P-type ohmic contact(NA=4.610¹⁸cm^-3), which contains multiple-layer metals including Ti/Al/Au, isobtained with its specific contact resistance of9.5510^-3Ω cm².Before fabrication, the device layout and process flow is carefully designed. Onthe basis of so many preparation, the device with its common emitter DC gain of17,the specific on resistance of32mΩ·cm²and the open base breakdown voltage of120V, is accomplished. Thereinto, the common emitter DC gain is currently thebest results in China.In this paper, structure design and manufacturing process of4H-SiC power BJTis lucubrated, which is an important reference value for the fabrication of4H-SiCpower devices.