Structural and electrical properties of Si-doped a-plane GaN grown on r-plane sapphire by MOVPE

Optical and electrical properties of Si-doped in a-plane GaN grown on r-plane sapphire

“…The results showed that the XRC-FWHM value of the (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) plane along the c-axis direction and m-axis direction increased with increasing SiH 4 flow rate, which demonstrated that the crystalline quality along the c-axis direction slightly decreased. It means that the dislocation density increases with increasing SiH 4 flow rate.…”

“…Bei et al considered that the there are many dangling bonds along the edge dislocation lines, which provides acceptor traps and forms negatively charged Coulombic scattering centers in n-type GaN. Because the edge dislocation density decreases with increasing SiH 4 flow rate, the density of the negatively charged Coulombic scattering centers decreases accordingly, which eventually leads to mobility increasing [15]. It should be noted that the (0002) plane XRC-FWHM value of the Si-doped a-plane GaN was only 8% lower, but the mobility increased 10 times.…”

“…To circumvent this problem, a material growth with non-polar crystal orientation was developed [1][2][3]. Masayuki et al analyzed a non-polar type a-plane (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) AlGaN/GaN HFET free from polarization, and concluded that the polarization was not formed perpendicular to the heterointerface so the device could allow nearly normally-off operations [4]. However, the extended defect densities in non-polar a-plane (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) GaN were yet very high according to the state-of-the-art of material growth technology.…”

“…Masayuki et al analyzed a non-polar type a-plane (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) AlGaN/GaN HFET free from polarization, and concluded that the polarization was not formed perpendicular to the heterointerface so the device could allow nearly normally-off operations [4]. However, the extended defect densities in non-polar a-plane (11)(12)(13)(14)(15)(16)(17)(18)(19)(20) GaN were yet very high according to the state-of-the-art of material growth technology. For the a-plane (11-20) GaN on r-plane (1-102) grown by metal organic chemical vapor deposition (MOCVD), there occurred a TD density of 3×10 10 cm −2 and a basal stacking fault density of 3.5×10 5 cm −1 [5].…”

Milliwatt-class non-polar a-plane InGaN/GaN light-emitting diodes grown directly on r-plane sapphire substrates

“…The observed FWHMs were 349 arcsec for the c-axis direction and 533 arcsec for the m-axis direction. The FWFMs indicate that the defect density of a-plane GaN was still higher than that of conventional c-plane GaN, even though our growth method was still effective in obtaining high-quality a-plane GaN crystalline films [14,15]. Fig.…”