Metalorganic Surface Chemical Adsorption Deposition of AlN Films by Ammonia and Trimethylaluminum

Abstract

Experiments were carried out to investigate the feasibility of metalorganic surface chemical adsorption deposition (MOSCAD) for growing aluminum nitride (A1N). This technique tends to promote only surface reactions, confining the decomposition, interactions between intermediates and deposition processes necessary for crystal growth to the substrate surface. As a result, low-temperature deposition becomes possible. Epitaxial A1N growth was demonstrated at a temperature as low as 400~ The A1N film, grown at a rate of 1.5-2.0 ~m/h, was visually observed to be transparent with a specular surface. The examination of the film by scanning electron microscopy at a magnification of twenty thousand revealed the featureless surface. X-ray diffraction of the film exhibited a single peak associated with A1N. Quantitative analysis by Auger electron spectroscopy revealed that only A1 and N were present in a ratio close to unity. These results indicate that MOSCAD is a viable alternative to MOCVD for AIN growth at a low temperature under atmospheric pressure.

Effect of residual H 2 O on epitaxial AlN film growth on 4H-SiC by alternating doses of TMA and NH 3

“…Under the condition eliminating any present moisture, the AlCH x radicals with dangling bonds generated by the TMA decomposition survives and contributes to film growth as discussed in the previous report (the second panel of Fig. 1(c)) [15].…”

“…MOCVD processes below the NH 3 decomposition temperature are also possible via the surface reaction. The heterogeneous decomposition of TMA starts to appear at 300 • C [14,15]. When TMA thermally decomposes on the surface, it tends to produce dangling bonds, such as AlCH 2 , AlCH 3 , and AlCH radicals.…”

“…When TMA thermally decomposes on the surface, it tends to produce dangling bonds, such as AlCH 2 , AlCH 3 , and AlCH radicals. The reactive radicals dissociate adjacent NH 3 molecules, despite the NH 3 decomposition temperature being above 800 • C. As a result, AlN growth is available without the interference of gasphase decomposition reactions [15]. In the case of epitaxial AlN film growth, many efforts have been made to lower the deposition temperature; however, the film should be grown higher than 1000 • C [13].…”

MOVPE growth of InN films and quantum dots

“…It is believed that NH 3 decomposes on the surface by reaction with TMIn or its decomposition products [28][29][30]. So, there is a compromise in obtaining the optimum V/III molar ratio, since the injected ammonia must be large enough to permit InN growth, but must not result in an excess amount of H 2 , which will ''etch'' the layer.…”

Atomic Layer Epitaxy Growth of AIN Thin Films

“…AlC13-NH3. Recently, Yu et al [2] demonstrated that in the Al(CH3)3 -NH3 CVD process the growth temperature can be lowered down to 400 "C by confining all the film forming reactions on the substrate surface, thus eliminating possible gas phase reactions including the adduct formation. Likewise, Asif Khan et al [3] reported that while temperatures exceeding 700 "C were needed in a conventional CVD to grow epitaxial AlN films from Al(C2H5)3 and NH3, the Atomic Layer Epitaxy (ALE) technique was capable of producing films with a high quality already at 450 "C. As distinct from CVD, in ALE the precursors are led onto the substrate alternately [4,5].…”