Improvement of Structural Properties of GaN Pendeo-Epitaxial Layers

Abstract

The effects of growth parameters on growth behavior of Pendeo‐epitaxial GaN layers in 〈1$ \bar 1 $00〉 patterned GaN seed stripes on sapphire were systematically investigated to improve the structural properties of the overgrown layers. It was found that the ratio of lateral to vertical growth rate (γ) is strongly affected by changes in growth temperature, reactor pressure, and V/III ratio, which have an effect on the distribution of crystallographic tilt among the wing regions. Also, the crystallographic anisotropy, which was determined from the results of (0002) X‐ray diffraction rocking curves taken perpendicular and parallel to the seed stripe direction, can be improved with relatively high V/III ratio.

Microstructural analysis of GaN films grown by a two-step technique on patterned GaN and sapphire

“…2(d). However, the growth conditions with the triangular GaN films cause the retardation of the coalescence of the wing region and the crystallographic tilting [8]. Because the bending of threading dislocations is mostly accomplished at the initial growth, as shown in Fig.…”

“…The regrowth at the lower temperature resulted in the retardation of the coalescence of wing regions (window region) and must perform thick film growth for the complete coalescence on the surface. Also, it has been reported that the decrease of the γ ratio increased the degree of crystallographic tilt [8]. Therefore, most of the regrowth should be deposited at higher temperature and lower reactor pressure for the promotion of lateral growth.…”

High rate photoelectrochemical etching of GaN and the use of patterned substrates for HVPE regrowth

“…The large height of the stripes, as well as the intervals between them provides much space for lateral growth of GaN. Thus it should be possible to obtain low-dislocation material in the form of stripes, wider than those reported by other authors [1][2][3][4][5]. Low-dislocation stripes width is crucial for the production of high-power laser diodes.…”

“…The most widely used methods are ELOG [1,2] and pendeoepitaxy [3][4][5]. However, they provide low-dislocation-density material in the form of stripes of 3-5 mm which is insufficient for high-power laser diodes.…”

Structural and Optical Properties of Lateral Overgrown GaN Grown by Double Pendeo‐Epitaxy Technique

“…That means that the crystallo- graphic tilts of wing layers did not occur during their overgrowths. It is known that the crystallographic tilt is strongly affected by the ratio of the lateral to vertical growth rate (g) under various growth conditions such as growth temperature, reactor pressure and V/III [9]. In the case of relatively high g (g > 2) or low g (g < 0.7), the tilt at wing regions was dramatically decreased.…”