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

Abstract

We studied the dynamics of the expansion of a Shockley-type stacking fault (SSF) with 30° Si(g) partial dislocations (PDs) using a scanning electron microscope. We observed SSFs as dark lines (DLs), which formed the contrast at the intersection between the surface and the SSF on the (0001) face inclined by 8° from the surface. We performed experiments at different electron-beam scanning speeds, observing magnifications, and irradiation areas. The results indicated that the elongation of a DL during one-frame scanning depended on the time for which the electron beam irradiated the PD segment in the frame of view. From these results, we derived a formula to express the velocity of the PD using the elongation rate of the corresponding DL during one-frame scanning. We also obtained the result that the elongation velocity of the DL was not influenced by changing the direction in which the electron beam irradiates the PD. From this result, we deduced that the geometrical kink motion of the PD was enhanced by diffusing carriers that were generated by the electron-beam irradiation.

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

“…For this reason the approach used in Ref. [12], which assumes that a dislocation segment moves only when it is inside the generation volume cannot be applied. As shown in Figure 3a, the irradiation outside SSF can also enhanced the dislocation glide at least at distances solidi physica a up to 25 μm from the irradiation point, which is essentially larger than the measured diffusion length value.…”

“…[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.…”

“…although the phase transformation to 3C‐SiC observed after nanoindentation at room temperature can be also considered as an indication of SSF generation. It is widely accepted that the expansion of single SSFs under excess carrier injection is driven by a 30°Si(g) glide . However, it is not so obvious for SSFs introduced by plastic deformation at elevated temperatures because the results obtained in Ref.…”

“…Understanding the detailed mechanisms of Shockley‐type stacking fault (SSF) nucleation and the driving force for their expansion is very important for suppressing their harmful effect on the degradation of power devices based on 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.…”

“…It is widely accepted that the expansion of single SSFs under excess carrier injection is driven by a 30 Si(g) glide. [4,6,11,12,14] However, it is not so obvious for SSFs introduced by plastic deformation at elevated temperatures because the results obtained in Ref. [9] allow to imply that the SSF expansion under low energy electron beam irradiation (LEEBI) and by thermal excitation is driven by partial dislocations of different types.…”