Synthesis and Growth of Gallium Nitride by the Chemical Vapor Reaction Process (CVRP)

Abstract

A new process for synthesis and bulk crystal growth of GaN is described. GaN single crystal c-plane platelets up to 9mm by 2mm by 100 µ m thick have been grown by the Chemical Vapor Reaction Process (CVRP). The reaction between gallium and a nitrogen precursor is produced by sublimation of solid ammonium chloride in a carrier gas, which passes over gallium at a temperature of approximately 900 ° C at near atmospheric pressures. Growth rates for the platelets were 25-100 µ m/ hr in the hexagonal plane. Seeded growth in the c-direction was also accomplished by re-growth on previously grown c-plane platelets. The crystals were characterized by X-ray diffractometry, atomic force microscopy, secondary ion mass spectrometry, inert gas fusion, and room temperature Hall effect and resistivity measurements.

Growth of cubic GaN crystals from hexagonal GaN feedstock

“…Anhydrous ammonia was condensed (at À196 1C) into a 8 mm OD/4 mm ID or a 8 mm OD/5 mm ID quartz tube containing GaN and any salt additives, and the tube was flame-sealed at a height as noted in Table 1. Most of the source h-GaN was obtained from a chemical vapor reaction process [11]. The tubes were heated in a pressurized hydrothermal system and the products were isolated in a manner identical to that reported previously [1,3,4,9].…”

Synthesis of dense polycrystalline GaN of high purity by the chemical vapor reaction process

“…Argoitia et al [9] demonstrated that molten Ga reacts with atomic nitrogen to form a thick crust of polycrystalline GaN. This paper reports an improvement to the previous processes [7][8][9] using ammonia for low cost commercial production of polycrystalline nitride bulk material. Synthesis of highpurity, dense polycrystalline GaN was accomplished.…”

“…In 1999 we reported a new process called the chemical vapor reaction process (CVRP) to synthesize gallium nitride [7] and to manufacture nitride targets for use in sputtering and similar equipment [8]. All GaN obtained by these processes, however, are either small needles or powder agglomerations of low density, which require high-temperature and high-pressure sintering to produce high-density polycrystalline bulk for source material.…”

Growth of A1N by the chemical vapor reaction process and its application to lateral overgrowth on patterned sapphire substrates

“…The chemical vapor reaction process (CVRP), which was first proposed for GaN growth by Callahan et al [15] is one of the candidates to achieve high A1N growth rates. In the case of GaN, the growth rate has reached 100 mm/h.…”