Surface treatments toward obtaining clean GaN(0001) from commercial hydride vapor phase epitaxy and metal-organic chemical vapor deposition substrates in ultrahigh vacuum

Preparation of gallium nitride surfaces for atomic layer deposition of aluminum oxide

“…[11][12][13] Studies have demonstrated success in removing the native oxide on GaN using various wet cleaning procedures. 14,15 Additionally, there have been reports of improvement in oxide quality on GaN after exposure to trimethylaluminum (TMA) and atomic hydrogen prior to atomic layer deposition (ALD). 16 This effect is well documented on other III-V materials, as well.…”

Structure, Morphology, and Stoichiometry of GaN(0001) Surfaces Through Various Cleaning Procedures

“…A hydrogen concentration of 10 19 -10 23 cm −3 was measured for molecular beam epitaxy (MBE)-GaN by nuclear reaction analysis, and a strong correlation between hydrogen concentration and crystal strain (dislocations) was observed. This correlation leads to a higher density of the hydrogen impurity in metal-organic chemical vapor deposition (MOCVD) films than in HVPE substrates (Hattori et al, 2009), affecting the dislocation density, when the hydrogen impurity is supplied from the source gases.…”

“…However, there is no standard method of preparing GaN substrates using chemical solutions or by ultra high-vacuum (UHV) treatment, and the results obtained in previous studies were not in conformity with one another. Through the various processes of cleaning GaN(0001) surfaces, we found a strong interrelation between surface morphology and stoichiometry; rough surfaces have broken stoichiometry while flat surfaces retain their stoichiometry (Hattori et al, 2009;2010). equilibrium diagram.…”

“…This implies that the HVPE growth conditions are not yet optimized. In the TPD of MOCVD samples, no GaCl desorption and little Cl desorption were detected (Hattori et al, 2009). In the MOCVD process, the gallium and nitrogen sources are usually Ga(CH 3 ) 3 and NH 3 , respectively, and the products are GaN and CH 4 :G a ( C H 3 ) 3 +N H 3 → GaN + 3CH 4 (Amano et al, 1986).…”

“…The details of experimental condition and all references were written in Ref. (Hattori et al, 2009;2010).…”