DLTS study on Al+ ion implanted and 1950°C annealed p-i-n 4H-SiC vertical diodes

A vertical 4H-SiC p-i-n diode with 2x10
²⁰
cm
^-3
Al
⁺
implanted emitter and 1950°C/5min post implantation annealing has been characterized by deep level transient spectroscopy (DLTS). Majority (electron) and minority (hole) carrier traps have been found. Electron traps with a homogeneous depth profile, are positioned at 0.16, 0.67 and 1.5 eV below the minimum edge of the conduction band, and have 3x10
^-15
, 1.7x10
^-14
, and 1.8x10
^-14
cm
²
capture cross section, respectively. A hole trap decreasing in intensity with decreasing pulse voltage occurs at 0.35 eV above the maximum edge of the valence band with 1x10
^-13
cm
²
apparent capture cross section. The highest density is observed for the refractory 0.67 eV electron trap that is due to the double negative acceptor states of the carbon vacancy.