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采用富碲垂直液相外延技术实现了50 mm×50 mm×3高性能碲镉汞外延材料的制备.外延工艺的样品架采用了三角柱体结构,并设计了防衬底背面粘液的样品夹具.为保证大面积材料的均匀性,工艺中加强了对母液温度均匀性和组分均匀性的控制,50 mm×50 mm外延材料的组分均方差达到了0.000 4,厚度均方差达到了0.4μm.在批量生产技术中,加强了对单轮次生长环境的均匀性和生长轮次之间生长条件一致性的控制,同一轮次生长的3片材料之间的组分偏差小于0.000 4,厚度偏差小于0.1μm,不同生长轮次之间材料的组分之间的波动在±0.002左右,厚度之间的波动在±2μm左右.工艺中对碲锌镉衬底的Zn组分、缺陷尺寸和缺陷密度也加强了控制,以控制大面积外延材料的缺陷,晶体双晶衍射半峰宽(FWHM)小于30弧秒,外延材料的位错密度小于1×105cm~(-2),表面缺陷密度小于5 cm~(-2).外延材料经过热处理后,汞空位型的P型Hg0.78Cd0.22Te外延材料77 K温度下的载流子浓度被控制在8~20×1015cm-3,空穴迁移率大于600 cm2/Vs.材料整体性能和批生产能力已能满足大规模碲镉汞红外焦平面探测器的研制需求.
The fabrication of 50 mm × 50 mm × 3 high-performance tellurium-mercury-cadmium oxide epitaxial material was achieved by using tellurium-rich vertical liquid phase epitaxy, and the sample holder of the epitaxial process adopted a triangular prism structure and a sample holder with a backing-backed mucus was designed. In order to ensure the uniformity of large area materials, the temperature uniformity and composition uniformity of the mother liquor were enhanced in the process. The mean square deviation of the composition of the 50 mm × 50 mm epitaxial material was 0.000 4 and the mean square deviation of the thickness reached 0.4 μm In batch production technology, the uniformity of growth environment between single growth cycle and growth cycle was strengthened, and the component deviation between the three materials grown in the same cycle was less than 0.0004. The thickness The deviation is less than 0.1μm, the fluctuation of the composition of the material between different growth rounds is about ± 0.002, and the fluctuation between the thicknesses is about ± 2μm.The Zn composition, defect size and The defect density is also controlled to control the defects of the large area epitaxial material. The FWHM of the crystal is less than 30 arcsec, the dislocation density of the epitaxial material is less than 1 × 10 5 cm -2, the surface defect density Less than 5 cm ~ (-2). Extrusions pass through the heat , The carrier concentration of Hg0.78Cd0.22Te P-type Hg0.78Cd0.22Te epitaxial material with mercury vacancy is controlled at 8-20 × 1015cm-3 at 77 K and the hole mobility is more than 600 cm2 / Vs. Production capacity has been able to meet the large-scale development of HgCdTe infrared focal plane detector needs.