High Nitrogen Doping During Bulk Growth of SiC

Macroscopic Approach to the Nucleation and Propagation of Foreign Polytype Inclusions during Seeded Sublimation Growth of Silicon Carbide

“…This growth sector appears a little darker within the doped stripes, which is attributed to a higher incorporation of nitrogen on the C-polar facet than elsewhere. 19,20 In this section, three different polytype inclusions were seen. Their starting points, indicated by the red circles, are all located in the (000-1) growth sector.…”

“…The other two (circles 2 and 3 in Figure 2a) are thin 15R−SiC lamellae, i.e., they do not expand axially in the [000-1] direction. Once formed on the facet, inclusions expand laterally following the step propagation toward the [11][12][13][14][15][16][17][18][19][20] direction and spread all along the crystal diameter. A higher magnification picture of inclusions 1−3 is shown in Figures 2b−d.…”

“…The consequence is the occurrence of two (000-1) facets at both sides of the section. On the right-hand side facet, three 6H−SiC thin lamellae nucleate, indicated by circles 1−3 (Figure 3a), and expand toward the [11][12][13][14][15][16][17][18][19][20] direction. On the left-hand side facet, a thick 15R−SiC inclusion nucleates (left side of Figure 3).…”

“…To resolve the geometrical evolution of the crystal, we quantified both normal (along the [000-1] direction) and lateral (along the [11][12][13][14][15][16][17][18][19][20] direction) growth rates. Also, the lateral propagation of the polytype inclusions (A1−A3 and B1− B3 for inclusions 1−3 of crystals A and B, respectively) was systematically evaluated.…”

New insight into the microstructure and doping of unintentionally n-type microcrystalline silicon carbide

“…In the literature, O and N impurities originating from contamination are discussed as possible candidates for the creation of donor-like states within the energy gap of lcSiC:H. 2,6,7 From c-SiC it is well known that N is a very good shallow donor impurity, due to its low ionization energy. 28 Unlike the case of unintentionally n-type doped microcrystalline silicon, where the use of gas purifiers during deposition decreased [O] and r d , 29 Finger et al 2 reported that the electrical properties of unintentionally n-type doped lcSiC:H were not affected by gas purifiers. In the present work, although r d covers a very large range-9 orders of magnitude- [O] In the following we discuss two plausible options that might explain the strong increase of r d , which is dominated by an increase of n, without any increase of the donor impurity concentrations.…”