Abstract
A carrier channel with gradient distributing element concentration includes a substrate and a piling layer. The piling layer is formed by piling a material on the substrate. The piling layer includes a contact surface contacting with the substrate. The material crystallizing by the rapid melt growth is used as a carrier channel. The carrier channel has h gradient distributing element concentration, and the aspect ratio of the carrier channel is greater than one. Therefore, the device can change the section of the carrier channel adapting to their characteristics, and the devices adjust the element concentration without additional processes. Finally, the rapid melt growth needs less process time and it can reduce thermal budget and production cost.