Lateral epitaxy

It should be noted that a reduction in the threading dislocation density in GaN has been achieved through the application of selective area epitaxy and lateral epitaxial overgrowth ((LEO), also known as epitaxial lateral overgrowth (ELO), or epitaxial laterally grown GaN (ELOG)). This epitaxial technique is discussed in Datareview B2.10 in this book. 

B2.10 Lateral epitaxy and microstructure in selectively grown GaN on SiC substrates... 

Historically, the ELO technique was first developed in Si [16] and then in III-V compounds such as GaAs [17] and InP [18] for obtaining high-quality crystal layers on an Si02 intermediate layer. The aim has been to fabricate new types of device and to realise the cleavage of lateral epitaxial films for transfer (CLEFT) method. This method was also found to be very effective for reducing threading... 

Cl Microstructure and Lateral Epitaxy of Selectively Grown GaN Hexagonal Pyramids... 

FIGURE 20.16 In a second 3D fabrication scheme, CMP is used to smooth the wafer surface after lateral epitaxial growth. After a first layer of transistor fabrication, a second layer of device quality Si is grown from seed holes in Si02 down to the original wafer surface. This process allows for transistor fabrication on multiple levels of the wafer surface (from Ref. 15). 

Fig. 9 (A) Schematic illustration of the VLSE process. (B) Tilted SEM image of vertical Si nanowire array grown on a (111) Si wafer. (C) Tilted SEM image of Si nanowire array grown on Si(l 0 0). (From Ref. f) Three of the four equivalent (111) directions are indicated by the white arrows. (D) Cross-sectional SEM images of a 4 im-wide, anisotropically etched trench in a Si(l 1 0) wafer. (E) Au-catalyzed, lateral epitaxial nanowire growth across an 8 tm-wide trench, connecting to opposing sidewall. (From Ref.P f)...

Figure 4 - Baman phonon frequency of laser-recrystallized lateral epitaxially annealed silion on Insulating oxide (SOI) and the derived stress, as a function of distance from the seed/SOI Interface Spectra were acquired with laser wavelengths 514.5 and 457.9nm.

Figure 5.8 Cross-sectional TEM images of GaN films on (a) nonporous SiC substrate, and (b)-(d) on porous SiC substrates. The label ps denotes a porous substrate and np denotes a nonporous substrate. The surface pore density of the substrate in (b) is 13 prrr2, and in (c) and (d) is 11.5 pm-2. The open tubes in the GaN films on porous substrates are marked by T (the tubes appear white in contrast near the top of the film where they are empty, and black near the interface where they are filled by Ga). The regions labeled D contain a relatively low number of threading dislocations originating at the interface (due to the lateral epitaxial growth over the substrate pores), and they contain dislocation half-loops gliding in from tubes. One half-loop is faintly seen to the right of a in (c). Reproduced from A. Sagar et al., J. Vac. Sci. Technol. B 21, 1812. Copyright (2003), with permission from the American Institute of Physics...

Figure 5.9 Magnified images of GaN on porous 6H-SiC. The half-loops are clearly seen in (a), with some of them indicated by arrows. The region marked by D in (b) shows nearly defect-free GaN due to the lateral epitaxial growth over the pores. The open tubes are marked by T ...

T. S. Zheleva, O.-H, Nam, M. D. Bremser and R. F. Davis, Dislocation density reduction via lateral epitaxy in selectively grown GaN structures , Appl. Pbys. Lett., 71,2472 (1997). 

GaN Lateral Epitaxy Growth Using Porous SiNx, TiNx and SiC... 

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