Drastic reduction of crystallization time during Al-induced crystallizaion of amorphous Si by Ge adlayer

We investigated influence of Ge adlayer at amorphous Si (a-Si)/Al interface on the Al-induced crystallization process of a-Si by using in-situ monitoring system, and disclosed that drastic reduction of crystallization time is possible by inserting Ge with a thickness of only a few nm. The microstructures of the grown polycrystalline films are strongly dependent on the thickness of the Ge adlayer. When the thickness of Ge is 1 nm, the average grain size was almost twice compared with the control sample (without Ge). However, further increase of Ge resulted in decrease of the grain size due to the increase of the nucleation rate. Therefore, an optimum thickness of Ge is considered to exist at a given crystallization temperature to minimize processing time while controlling microstructures.