[21p-S423-1~19] 13.9 Optical properties and light-emitting devices

▼ [21p-S423-9] Comparison of GPS and HIP methods for Si-doped AlN powders synthesis

〇(D)Yujin Cho^1,2, Kohsei Takahashi², Benjamin Dierre², Takashi Takeda², Naoki Fukata², Naoto Hirosaki², Takashi Sekiguchi^2,1 (1.Tsukuba Univ., 2.NIMS)

Keywords:Si-doped AlN,Gas pressure sintering,Hot isostatic pressure

Gas Pressure Sintering (GPS) and Hot Isostatic Pressing (HIP) processes are standard pressure-assisted methods to synthesize nitride/oxynitride phosphors. In the previous study, we have used GPS technique to synthesize Si-doped AlN powders for UV emitting phosphors [1]. The experimental results suggested that the synthesis temperature and N₂ pressure should be higher than the typical GPS conditions. Since HIP can apply higher temperature and pressure to the specimen (GPS: ~2200°C/~1 MPa, HIP: ~2500°C/ ~200 MPa), it seems preferable to use HIP for Si-doped AlN powder sintering.
In this study, we have prepared the series of Si-doped AlN powders doped with different Si concentrations and synthesized them by HIP process under 1950°C and 150 MPa N₂. The structural, chemical and luminescent properties of obtained powders were compared with those made by GPS process.
Fig.1 is the cross-sectional SE-CL images of 1.6% Si-doped AlN powder sintered by GPS and HIP, respectively. These data showed that GPS powders were coated by Si-N layers and promoted particle growth. On the other hand, HIP powders contained SiAlON particle. These difference are attributed to the different gas flow conditions of two methods. The reason of the discrepancy will be discussed in the presentation.