Adsorption, Desorption, and Reaction of a Gallium Nitride Precursor, (H2GaNHNMe2)2, on HfO2

The adsorption, desorption, and reaction of a dimeric gallium nitride precursor, (H2GaNHNMe2)2, on amorphous HfO2 are studied using TPD, AES, isothermal reaction spectroscopy (IRS), and temperature-programmed reaction (TPR). When dosed below 120 K, (H2GaNHNMe2)2 adsorbs and desorbs molecularly and TPD results are consistent with a phase-transition model involving a low-temperature phase (phase A) that transforms irreversibly, between 190 and 215 K in competition with desorption, to a slightly more stable phase (B). The IRS, TPR, and AES data show that the dimers dissociate to monomers during dosing at 355 K, that GaN starts to form at 550 K, and that film-forming reactions become fast at 575 K. The results are consistent with monomer N-N bond cleavage to form hydrides, H2GaNH and HGaNH, that eliminate hydrogen to produce GaN. The GaN films are examined using X-ray diffraction (XRD) and scanning electron microscopy (SEM