Results　on　AI-induced　crystallization　of　amorphous　Ge　(a-Ge)　deposited　by　vacuum　thermal　evaporation　techniques　under　thermal　annealing　in　N-2　atmosphere　are　presented　in　detail.　The　a-Ge　crystallization　and　fractal　Ge　pattern　formation　on　the　free　surface　of　annealed　Al/Ge　bilayer　films　deposited　on　single-crystal　Si　(100)　substrates　were　investigated　by　using　scanning　electron　microscopy　(SEM),　X-ray　diffraction　(XRD),　atomic　force　microscopy　(APM),　energy　dispersive　X-ray　spectrometry　(EDS),　and　Raman　spectra.　It　is　found　that　the　temperature　field　effects　play　an　extremely　crucial　role　in　a-Ge　crystallization　and　fractal　Ge　formation　process.　The　open　branched　structure　of　fractal　Ge　clusters　in　Al/Ge　bilayer　films　was　effectively　prepared　by　Al-induced　crystallization　when　they　were　annealed　at　400　degrees　C　for　60　min.　These　films　with　fractal　Ge　clusters　exhibit　charming　noninteger　dimensional　nanostructures,　which　differ　from　those　of　conventional　integer　dimensional　materials　such　as　one-dimensional　nanowires/nanorods,　nanotubes,　nanobelts/nanoribbons,　two-dimensional　heterojunctions,　thin　films,　and　zero-dimensional　nanoparticles.　The　SEM　image　shows　that　a　big　Al　grain　was　found　located　near　the　center　of　a　fractal　Ge　cluster　after　the　films　were　annealed　at　400　and　500　degrees　C　for　60　min.　This　suggests　that　the　grain　boundaries　of　polycrystalline　Al　films　are　the　initial　nucleation　sites　of　a-Ge.　It　also　validates　the　preferred　nucleation　theory　of　a-Ge　at　triple-point　grain　boundaries　of　polycrystalline　Al　at　the　interface.　This　discovery　may　be　explained　by　the　metal-induced　nucleation　(MIN)　mechanism.