未退火Co/n-poly-SiGe肖特基接触不均匀性研究

Study on Inhomogeneous Schottky Contact of As-Deposited Co/n-Poly-SiGe

在n型单晶硅衬底上,用射频磁控溅射法沉积Si1-xGex薄膜,在850℃下对薄膜进行40min磷扩散,制备出n-poly-Si1-xGex。俄歇电子谱(AES)测试表明,Si1-xGex薄膜的Ge含量约为18%,即磷扩散后得到n-poly-Si0.82Ge0.18。随即在n-poly-Si0.82Ge0.18薄膜上溅射一层Co膜,形成Co/n-poly-Si0.82Ge0.18肖特基结。在90K～332K温度范围内,对样品进行变温I-V测试(I-V-T)。发现随测试温度的升高,表观理想因子na变小,肖特基势垒高度(SBH)变大。这是金属/半导体肖特基接触不均匀性的表现,对这种不均性进行建模,并和实验数据进行对比,两者基本符合。

Si1-xGex films were deposited by RF magnetron sputtering on n-type monocrystalline Si substrate.Measurement with Auger electron spectrum（AES） showed that Ge percentage in the as-deposited Si1-xGex film was approximately 18%.Si0.82Ge0.18 films were doped with phosphorus at 850 ℃ for 40 min using thermal diffusion to form n-type polycrystalline films（n-poly-Si0.82Ge0.18）.And Co/n-poly-Si0.82Ge0.18 Schottky junctions were made by sputtering,on which variable temperature I-V tests were conducted in the temperature range from 90 K to 332 K.It has demonstrated that,with increasing test temperature,apparent ideal factor decreased and Schottky barrier height（SBH） increased.These phenomena incarnated the inhomogeneity of SBH at Co/n-poly-Si0.82Ge0.18 interface.A model describing inhomogeneous SBH was established based on literatures.Modeling results were in good agreement with experimental data.