快速热退火对Co/Si_(0.85)Ge_(0.15)肖特基结电学特性的影响

Effects of Rapid Thermal Annealing on The Physical and Electrical Properties of Co/Sputtered-Si_(1-x)Ge_x Schottky Junction

用离子束溅射技术分别在SiO2和单晶Si衬底上沉积了Si1-xGex和Co薄膜。在不同温度下,对Co/Si1-xGex肖特基结进行快速热退火处理(RTA),对处理后的样品进行了表面形貌和电学测量。发现退火温度升高,样品表面粗糙度变大,理想因子也变大,但对肖特基势垒高度(SBH)的影响很小。分析认为,随着退火温度的升高,金属/半导体界面缺陷态密度的增加是造成理想因子变大的主要原因。界面态对费米能级的"钉扎"以及固相反应生成锗硅化钴与Co的功函数大致相同,是SBH基本不随温度变化的主要因素。

Si1-xGex films were deposited by ion beam sputtering on SiO2 and monocrystalline Si substrates respectively.The Si1-xGex films were doped with phosphorus and boron respectively through thermal diffusion to form n-and p-type films.The Si1-xGex film is polycrystalline.And the Co/poly-Si1-xGex Schottky junctions were performed.The surface roughness and electrical properties were measured right after they were dealt with rapid thermal annealing（RTA） at different temperatures.With the increasing of annealing temperature,the surface roughness and the ideal factor characterizing the Schottky contact deviation from ideal status increase,while the Schottky barrier height（SBH） just changes slightly.The interfacial defect density increases with the annealing temperature increase,which is the main reason for the ideal factor going up.The Fermi level pinning effect originating from the interfacial state and Cobalt Germanium silicides formed by solid state reaction having almost the same work function with Cobalt itself are the two principal aspects responsible for nearly invariant SBH.