HIGH-PURITY POLYCRYSTALLINE SILICON SPUTTERING TARGET MATERIAL, PREPARATION METHOD THEREFOR AND USE THEREOF

摘要

A high-purity polycrystalline silicon sputtering target material, a preparation method therefor and use thereof. The preparation method comprises the following steps: (1) loading of a silicon material; (2) a melting stage; (3) a crystal growth process; (4) reduction of thermal stress; and (6) a cooling stage. The tailing material produced during a polycrystalline silicon ingot casting/purification process is used as a raw material. The polycrystalline silicon raw material having a lower purity is purified by means of electron beam smelting and coupling directional solidification to obtain a high-purity polycrystalline silicon material. The resistivity of the silicon target material is controlled by adding an aluminum boron alloy into the silicon. The grain orientation and uniformity are ensured by means of seed crystal induced directional solidification process. Crystal defect formation is inhibited by adjusting the solidification process. The yield of primary product obtained by the method can reach about 80%, and the method has advantages of having low cost, high purity, consistent crystallization orientation, low crystal defects, and controllable resistivity.