| 摘要 |
Embodiments described above provide mechanisms of forming contact structures with low resistance. A strained material stack with multiple sub-layers is used to lower the Schottky barrier height (SBH) of conductive layers underneath the contact structures. The strained material stack includes a SiGe main layer, a graded SiG layer, a GeB layer, a Ge layer, and a SiGe top layer. The GeB layer moves a Schottky barrier to an interface between GeB and metal germanide, which greatly reduces the Schottky barrier height (SBH). The lower the SBH, the Ge in the SiGe top layer forms the metal germanide, and the high B concentration in the GeB layer helps to reduce the resistance of the conductive layers underneath the contact structures. |
