坩埚预处理技术在氮化铝晶体生长工艺中的应用

在氮化铝晶体生长工艺中,坩埚的使用寿命是主要技术难点之一.实验发现,在钨坩埚体和盖之间放置内径和外径与坩埚相同的石墨环,在氮气环境下进行一次高温处理,使钨坩埚体与盖接触的部位形成碳化钨保护层,可以有效地解决高温下钨坩埚体与盖相粘结的问题,大大提高了坩埚的使用寿命.使用经过预处理的钨坩埚,用物理气相法生长出φ0.8mm×1.5mm氮化铝单晶体和φ36mm×5mm氮化铝多晶片.

Application of Pretreated Crucible Technology to the Growth of AlN Crystals

The lifetime of the crucible is one of the main difficulties in the growth process of AlN crystals.A graphite ring with the same internal and external diameters as the crucibles was inserted between the tungsten crucible and its lid.After a high-temperature pretreatment in nitrogen ambient for the crucible and graphite ring subassembly,a tungsten carbide protecting film was formed on the contacting area of the crucible and its lid.This pretreatment process can avoid effectively the bonding of the crucible and its lid,and increase greatly the crucible lifetime.By using the pretreated tungsten crucible,AlN single crystals of 0.8mm diameter and 1.5mm long and polycrystalline AlN boules of 36mm diameter and 5mm long were grown by physical vapor transport technology.