Separation of the Driving Force and Radiation-Enhanced Dislocation Glide in 4H-SiC

Abstract

Anomalous expansion of stacking faults (SFs) induced in 4H-SiC under electronic excitations is driven by an electronic force and is achieved by enhanced glide of partial dislocations. An experimental attempt to separate the two physically different effects has been made by conducting photoluminescence (PL) mapping experiments which allowed simultaneous measurements of partial dislocation velocity and SF-originated PL intensity the latter of which is proposed to be related to the driving force for SF expansion through the density of free excitons planarly confined in the SF.

Expansion of Shockley stacking fault observed by scanning electron microscope and partial dislocation motion in 4H-SiC

“…Maeda et al observed the linear shape of the leading edge of SSFs after the line scan of the laser beam by photoluminescence. 12 This situation of keeping the PD orientation is achieved by the fast migration of geometrical kinks on the whole PD segment. However, geometrical kinks are not considered to move thermally at room temperature because the migration barrier is reported to be as large as, for example, 1.85 eV.…”

“…The SSF expansion in 4H-SiC is induced by the inversion of the SSF formation energy to the negative sign by electron trapping (and holes as excitons), in addition to the enhanced mobility of 30 partial dislocations (PDs) with Si core atoms in the glide-set core structure (30 Si(g) PDs), which form the leading edge of the SSF. [6][7][8][9][10][11][12] Such enhancement of PD motion is widely observed in semiconductors and is known as radiation-enhanced dislocation glide (REDG). 13 There are some reports on the REDG effect in 4H-SiC.…”

Suppression of stacking fault expansion in a 4H-SiC epitaxial layer by proton irradiation

“…The expansion of 1SSFs originates from extended dislocations having Burgers vector of 1/3<11-20> on the (0001) basal plane, which are called basal plane dislocations (BPDs). 1SSFs between two partial dislocations are expanded during bipolar operation by gliding of partial dislocations, driven by the “negative” stacking fault energy due to the lowering of the electronic energy by carrier trapping at the stacking fault 13 – 18 . Similarly, double Shockley-type stacking faults (2SSFs) in heavily nitrogen-doped 4H-SiC undergo expansion during high-temperature annealing 19 – 24 .…”

Annealing and LEEBI Effects on the Stacking Fault Expansion and Shrinking in 4H‐SiC

“…It is well established that excess carrier injection in p‐i‐n diodes under forward bias or by excitation with light or electron beams at room temperature leads to the single SSF expansion . The energy gain due to electron capture into quantum wells associated with the SSFs (so‐called “quantum well action”) is widely considered as a driving force for SSF nucleation and expansion. Single SSFs can be also introduced by plastic deformation at temperatures higher than 573 K .…”

“…[1][2][3][4] It is well established that excess carrier injection in p-i-n diodes under forward bias or by excitation with light or electron beams at room temperature leads to the single SSF expansion. [2,[5][6][7][8][9][10][11][12] The energy gain due to electron capture into quantum wells associated with the SSFs (so-called "quantum well action") [13][14][15][16][17] is widely considered as a driving force for SSF nucleation and expansion. Single SSFs can be also introduced by plastic deformation at temperatures higher than 573 K. [9,10,18] although the phase transformation to 3C-SiC observed after nanoindentation at room temperature [19] can be also considered as an indication of SSF generation.…”