Figure 23

Phase diagram showing the energetically stable structures determined from first-principles calculations as a function of both Si (µ_Si) and N (µ_N) chemical potentials. The atomic geometry of these structures is shown in Figure 24. The limit at N-rich conditions is µ_Si = 1/3 H_f(Si₃N₄) and at Ga-rich conditions is µ_Si = 1/3 H_f(Si₃N₄) - 4/3 H_f(GaN). H_f(Si₃N₄) = -3.32 eV and H_f(GaN) = -1.24 eV are the calculated formation enthalpies of Si₃N₄ and GaN bulk, respectively. The shaded area shows the region where all structures are unstable against the formation of Si₃N₄. (From [66]).

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