Electrical Resistivity Control of Non-oxide Ceramics by Grain Boundary Phases

虽然AlN陶瓷本质上是绝缘体，但导电AlN陶瓷已被期望作为半导体制造设备中的机器部件。我们的研究小组报告说，通过沉淀低于2 vol. %的稀土碳氧化物晶界相，可以使AlN陶瓷导电而不失去其固有的高热导率。然而，导电AlN的断裂强度显着下降，因为AlN的晶粒生长的高温热处理的稀土碳氧化物晶界相的产生。为了通过降低烧结温度来抑制晶粒长大，对烧结助剂的组成进行了讨论。Y_2O_3-CeO_2复合添加剂的加入，在较低的烧结温度下致密化AlN，抑制了AlN晶粒长大，提高了AlN的断裂强度。此外，研究了绝缘晶界相的形成对SiC和AlN导电性的控制。通过<12>在两个面边界上析出绝缘晶界相，成功地将SiC的电阻率从10^3 Ωcm提高到10

Although AlN ceramics is intrinsically an insulator, the electrically conductive AlN ceramics has been expected as machine parts in semiconductor manufacturing equipments. Our research group has reported it is possible to render AlN ceramics electrically conductive without losing their intrinsic high thermal conductivity by precipitating a rare-earth oxycarbide grain boundary phase of below 2 vol.%. However, the fracture strength of conductive AlN remarkably decreased because of grain growth of AlN by high temperature heat treatment for production of rare-earth oxycarbide grain boundary phase. In order to inhibit considerable grain growth by decreasing sintering temperature, the compositions of sintering additives were discussed. The improvement of fracture strength of electrically conductive AlN was attained by addition of Y_2O_3-CeO_2 composite additive, which is possible to inhibit grain growth of AlN by densification at lower sintering temperature. Additionally, the control of electrical conductivity of SiC as well as AlN was studied by formation of insulating grain boundary phase. The resistivity of SiC was successfully enhanced to 10^<12> from 10^3 Ωcm by precipitating insulating grain boundary phase at two facial boundaries