Characterization of 4H-SiC Lattice Damage After Novel High Energy Ion Implantation

et al. 2022

MSF

Understanding the depth from which contrast from dislocations is still discernible (the effective penetration depth of the X-rays) in grazing-incidence synchrotron monochromatic beam X-ray topography is of great interest as it enables three-dimensional dislocation configuration analysis and accurate density calculations. To this end, systematic analysis has been performed of topographic and ray-tracing simulated contrast of basal plane dislocations with different Burgers vector and line direction combinations, and a universal method to determine the effective penetration depth based on ray tracing has been developed. This study reveals that the observable dislocation contrast depends on the effective misorientation associated with the dislocation modulated by the photoelectric absorption effect. The dislocations with larger effective misorientation tend to have longer projected length and correspondingly deeper effective penetration depths.

Section: Resultsmentioning

confidence: 84%

Section: Resultsmentioning

confidence: 99%

Ray-Tracing Simulation Analysis of Effective Penetration Depths on Grazing Incidence Synchrotron X-Ray Topographic Images of Basal Plane Dislocations in 4H-SiC Wafers

Cheng

et al. 2022

MSF

“…However, such implantation processes employing high energy ions can damage the lattice in the epilayers that can subsequently lead to lattice stress/strain, since the accelerated dopant atoms will displace the host Si and C atoms. Ion implantation at high energies with relatively low dose level is found to introduce tensile strains within the implanted 4H-SiC epilayers [3,4]. However, implantation with a higher dose level, of the order of 10 15 cm -2 , lattice stress/strain can possibly trigger the formation and migration of basal plane dislocations (BPDs) during the annealing process, which are known to be detrimental to the performance of the devices [5,6,7].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Basal Plane Dislocation Motion Induced by p+ Ion Implantation Using Synchrotron X-Ray Topography

Chen

Liu

et al. 2023

DDF

Self Cite

Multiple PIN diodes with junction termination extension (JTE) were fabricated on 4H-SiC wafers with 10 μm thick epilayers by ion implantation with various dosages of Al ions at room temperature (RT) and high temperature (600 °C). The subsequent annealing process was conducted at 1650 °C for 10 minutes to activate the dopant atoms and recover the lattice damages introduced by the implantation. Synchrotron X-ray topography was used to characterize the defects in the devices, and it is observed that basal plane dislocations (BPDs) were generated during the annealing process from the boundaries between the high (P+) and low (P-) doping concentration in devices implanted with relatively high doses at RT. Further, topographs also manifest motion of BPDs due to implantation-induced stresses, where BPDs with opposite sign Burgers vectors move in directions accommodative of nature of stress (tensile/compressive). On the other hand, generation of BPDs due to implantation was not observed in devices implanted either at relatively low dosages at both temperatures or relatively high dosages at high temperature. Measurements of blocking behaviors of devices illustrate that devices with higher densities of process-induced BPDs yield higher leakage currents.

“…Synchrotron X-ray plane wave topography (SXPWT) [8], (previously referred as synchrotron Xray rocking curve topography (SXRCT) [9,10,11]), is capable of measuring strain and tilt of 4H-SiC with a strain sensitivity of the order of 10 -6 . Wieteska, Wierzchowski and coworkers have observed various peaks and fringes in implanted Si and AlxGa1-xAs/GaAs epilayer by SXPWT, which show same angular positions as synchrotron rocking curve with double crystal monochromator [12,13].…”

Section: Introductionmentioning

confidence: 99%

Analysis of Strain in Ion Implanted 4H-SiC by Fringes Observed in Synchrotron X-Ray Topography

Chen

Liu

et al. 2023

DDF

Self Cite

A novel high energy implantation system has been successfully developed to fabricate 4H-SiC superjunction devices for medium and high voltages via implantation of dopant atoms with multi-energy ranging from 13 to 66 MeV to depths up to 12um. Since the level of energies used is significantly higher than those employed for conventional implantation, lattice damage caused by such implantation must be characterized in detail to enhance the understanding of the nature of the damage. In regard to this, by employing the novel high energy system, 4H-SiC wafers with 12μm thick epilayers were blanket implanted by Al atoms at energies ranging from 13.8MeV to 65.7MeV and N atoms at energies ranging up to 42.99MeV. The lattice damages induced by the implantation were primarily characterized by Synchrotron X-ray Plane Wave Topography (SXPWT). 0008 topographs recorded from the samples are characterized by an intensity profile consisting of multiple asymmetric diffraction peaks with an angular separation of only 2” (arcseconds). Using Rocking-curve Analysis by Dynamical Simulation (RADS) program, diffracted intensity profile was used to extract the corresponding strain profile indicating an inhomogeneous strain distribution across the depth of the implanted layer.