GaN PN-Structures Grown by Hydride Vapor Phase Epitaxy

Abstract

For the first time, GaN pn-junctions were fabricated by hydride vapor phase epitaxy. GaN pn-structures were grown directly on 6H-SiC substrates without any buffer layer. Undoped GaN layers were n-type with Nd-Na concentration ranged from 1×1017 to 5×1018 cm−3. Magnesium was used as an acceptor to grow p-type GaN layers. Mg atomic concentration determined by secondary ion mass spectroscopy ranged from 5×1019 to 5×1020 cm−3. As-grown GaN layers doped with Mg were p-type, and p-type conductivity was improved by post-growth anneal. Mesa diodes with a vertical current flow geometry were formed by reactive ion etching. The position of the GaN pn-junction was determined by the electron beam induced current method. The electrical characteristics of the pn diodes were studied. Electroluminescence from the pn diodes was measured.

Cathodoluminescence and Transmission Electron Microscopy Study of the Influence of Crystal Defects on Optical Transitions in GaN

“…Not intentionally doped 150 mm thick hexagonal``bulkº GaN has been epitaxially grown by Hydride Vapour Phase Epitaxy (HVPE) onto (0001) 6H-SiC substrates without any buffer layer [6]. The SiC substrate has then been removed by Reactive Ion Etching leaving free standing GaN samples for structural and optical investigations.…”

“…For reasons of completeness we may discuss other types of impurities that are very probably incorporated into the layer during growth like H and C. Due to the growth technique employed, a possible role of hydrogen and hydrogen complexes in the emissions under investigation should be considered. Following [17] and [18], in unintentionally doped n-type GaN samples like ours [6], H has a very low solubility and diffusivity and therefore the role of H has been neglected. With regard to C, first-principles based theoretical calculations [5] have demonstrated that in n-type GaN interstitial configurations of C have prohibitively high formation energies.…”

P-type GaN epitaxial layers and AlGaN/GaN heterostructures with high hole concentration and mobility grown by HVPE

“…Recently first HVPE grown p-type GaN layers and AlGaN/GaN pn structures have been demonstrated [4,5]. These results indicate a possibility to fabricate thick p-type GaN layers and possibly p-type GaN substrates by HVPE.…”

GROWTH AND ELECTRICAL/OPTICAL PROPERTIES OF AlxGa1−xN IN THE FULL COMPOSITION RANGE

“…The Al composition of x=0.45 was achieved with an n-type carrier concentration in the low 10 19 cm" 3 . Later on, Nicolaev et al 20 achieved high quality AlGaN alloy using an enhanced HVPE technique. The growth of both n-type 21 and p-type 20 AlGaN has been made available utilizing HVPE technique.…”

“…Later on, Nicolaev et al 20 achieved high quality AlGaN alloy using an enhanced HVPE technique. The growth of both n-type 21 and p-type 20 AlGaN has been made available utilizing HVPE technique. Recently, the same group demonstrated an all-HVPE LED 22 structure with emission at 341 nm, following the report of a submicron-thick multilayer growth.…”