Polycrystalline Si thin films on insulating substrates have been widely used to fabricate thin film transistors. However, since randomly induced grain boundaries in the polycrystalline thin films have been degrading transistor performance, application of thin film transistors has been limited to low speed processing units such as display drivers. Here, in this letter, we have tried to realize single grain growth of Si thin film at controlled position. Aluminum induced layer exchange crystallization of Si thin film was performed at limited region to suppress spontaneous nucleation during the crystal growth, and thus, single grain Si thin films have been successfully realized on quartz glass substrates. This technique will open up a way to realize high speed processing thin film transistors.