Electron mobility along 〈0001〉 and 〈1100〉 directions in 4H-SiC over a wide range of donor concentration and temperature

Abstract

Abstract We investigated the Hall electron mobility in 4H-SiC along and perpendicular to the c -axis ( μ H,// and μ H,⊥ ) using Hall bar structures fabricated on n-type SiC( <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>11</mml:mn> <mml:mover accent="true"> <mml:mrow> <mml:mn>2</mml:mn> </mml:mrow> <mml:mrow> <mml:mo stretchy="true">̅</mml:mo> </mml:mrow> </mml:mover> <mml:mo>0</mml:mo> </mml:math> ) epitaxial layers over a wide range of donor concentration (2.1 × 10 15 –3.2 × 10 18 cm −3 ) and temperature (298–600 K). We obtained μ H,// of 1160 cm 2 V −1 s −1 , which is the highest electron mobility ever reported for SiC measured at room temperature. The anisotropy of drift mobility becomes smaller at higher temperature and with higher donor concentration. This result can be qualitatively explained by smaller anisotropy of electron effective mass in the high-energy region of the conduction band.