背面多孔硅对SIMOX中铜杂质的吸除作用

Copper Gettering by Backside Porous Silicon in SIMOX Wafers

在SIMOX材料的背面成功地制备了多孔硅层,再在正面故意注入1×1015cm-2剂量的铜杂质。经900℃退火,二次离子质谱（SIMS）测试表明钢杂质能穿过理层SiO2并在背面多孔硅处富集。用剖面投射电子显微镜（XTEM）分析了埋层SiO2和背面多孔硅层的微观结构,背面多孔硅层及其多孔硅层同硅衬底之间“树技状”的过渡区被认为是铜杂质有效的吸除中心。

A porous silicon layer was successfully formed in the backside of SIMOX wafer, then copper was intentionally implanted at a dose of 1 × 1015 cm-2.After annealing at 900℃,secondary ion mass spectrometry(SIMS) measurements show that copper can diffuse through the buried SiO2 layer and concentrate in the backside porous silicon layer. The micro-structures of the buried SiO2 and the backside porous silicon layer were analyzed by cross-sectional transmission electron microscopy(XTEM). The backside porous silicon layer and the dendrite type interface betweem the porous silicon and the substrate silicon are regarded as very effective gettering sinks for copper impurity.