First experimental demonstration of SiC super-junction (SJ) structure by multi-epitaxial growth method

Abstract

A super-junction (SJ) device has been developed to improve the trade-off relationship between the breakdown voltage (V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BD</sub> ) and specific on-resistance in unipolar devices. Si-SJ devices are now widely used, and the effect of the SJ structure is also expected in SiC devices. Fundamental processes for fabricating SJ structures by using a multi-epitaxial (ME) growth method have been developed, where the epitaxial growth and MeV-class implantation steps are alternately repeated. Two types of test elemental groups (TEGs) were formed on the same wafer for evaluation of V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BD</sub> and the specific resistivity of the drift layer (R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">drift</sub> ). The measured V <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">BD</sub> was 1545 V, which was higher than that of the SiC theoretical limit by 670 V, and a value of R <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">drift</sub> (including the substrate resistance) of 1.06 mΩ·cm <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> was obtained.