Ultrathin highly uniform Ni(Al) germanosilicide layer with modulated B8 type Ni5(SiGe)3 phase formed on strained Si1−xGex layers

We present a method to form ultrathin highly uniform Ni(Al) germanosilicide layers oncompressively strained Si1xGex substrates and their structural characteristics. The uniform Ni(Al)germanosilicide film is formed with Ni/Al alloy at an optimized temperature of 400 C withan optimized Al atomic content of 20 at.%. We find only two kinds of grains in the layer. Bothgrains show orthogonal relationship with modified B8 type phase. The growth plane is identifiedto be {10-10}-type plane. After germanosilicidation the strain in the rest Si1xGex layer is conserved,which provides a great advantage for device application