Exploring the border traps near the valence band in the SiO2 - SiC system using above-band-gap optical …

Studying near-valence-band (<a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><a:msub><a:mi>E</a:mi><a:mi mathvariant="normal">V</a:mi></a:msub></a:math>) defects at the insulator–<e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><e:mi>n</e:mi></e:math>-type <h:math xmlns:h="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><h:mn>4</h:mn><h:mi>H</h:mi></h:math>-<k:math xmlns:k="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><k:mrow><k:mi>Si</k:mi><k:mi mathvariant="normal">C</k:mi></k:mrow></k:math> interface is challenging due to the low minority carrier concentration. Herein, we present a technique for characterizing the border traps near <o:math xmlns:o="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><o:msub><o:mi>E</o:mi><o:mi mathvariant="normal">V</o:mi></o:msub></o:math> in an <s:math xmlns:s="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><s:mi>n</s:mi></s:math>-type <v:math xmlns:v="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><v:mn>4</v:mn><v:mi>H</v:mi></v:math>-<y:math xmlns:y="http://www.w3.org/1998/Math/MathML" display="inline" overflow="scroll"><y:mrow><y:mi>Si</y:mi><y:mi mathvariant="normal">C</y:mi></y:mrow></y:math> MOS capacitor by generating holes using above-band-gap optical excitation (OE). A rise in capacitance was observed under OE (due to hole capture by border traps), remaining stable long after the optical stimulus was removed, resulting in a persistent photocapacitance effect. We show the dynamics of the capture process and perform a quantification of the captured holes in samples with thermally grown oxide and different postoxidation annealing treatments.