Effect of in-Situ Post-annealing on the Second Phase Inclusion Defects
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摘要: 采用传统布里奇曼法生长碲锌镉晶体，在配料过程中添加适当过量的Cd，并在晶体生长结束阶段的降温过程中加入晶锭原位退火工艺，晶体的第二相夹杂缺陷得到了有效抑制。根据晶体第二相夹杂缺陷的形成机理，结合热扩散理论和碲锌镉晶体的P-T相图，研究了退火温度对晶体第二相夹杂缺陷密度和粒度（尺寸）的影响，获得了抑制碲锌镉晶体第二相夹杂缺陷的退火条件。利用优化的退火条件制备碲锌镉晶体，晶体第二相夹杂缺陷的尺寸小于10 μm，密度小于250 cm－2。Abstract: Second-phase-inclusion defects in Bridgman-grown CdZnTe crystals were decreased via post-growth in-situ annealing combined with excess Cd in CdZnTe ingots. Based on the formation mechanism of the second-phase-inclusion defects in Bridgman-grown CdZnTe, the relationship between second-phase-inclusion defects and annealing temperature was studied. The size of second-phase-inclusion defects was reduced to less than 10 μm and their density to less than 250 cm-2 in CdZnTe at an optimized in-situ post-annealing temperature.
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Key words:
- CdZnTe /
- second phase inclusion defects /
- in-situpost-annealing
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图 1 碲锌镉晶体生长及原位退火过程，t1为晶锭头部的温度，t2为晶锭尾部的温度，t3为坩埚空腔的温度
Figure 1. Process of CdZnTe growth and annealing, temperature of the ingot tip (t1), temperature of the ingot tail (t2) and temperature of the crucible top (t3)
图 2 碲锌镉晶体第二相夹杂缺陷的形貌特征：(a)为Te的第二相夹杂缺陷，(b)为Cd的第二相夹杂缺陷
Figure 2. Second phase inclusion defects in CdZnTe, Te inclusion(a) and Cd inclusion(b)
图 3 不同组分碲锌镉晶体的P-T相图[8]：1. CdTe；2. Cd0.95Zn0.05Te；3. Cd0.85Zn0.15Te；4. Cd0.5Zn0.5Te；5. Cd0.2Zn0.8Te；6. Cd0.1Zn0.9Te；7. ZnTe；8. Ref[13]；9. Ref[13]；10. Ref[14]
Figure 3. P-T phase diagram of CdZnTe[8]: 1. CdTe; 2. Cd0.95Zn0.05Te; 3. Cd0.85Zn0.15Te; 4. Cd0.5Zn0.5Te; 5. Cd0.2Zn0.8Te; 6. Cd0.1Zn0.9Te; 7. ZnTe; 8. Ref[13]. 9. Ref[13]; 10. Ref[14]
图 4 不同空腔温度t3（Cd分压）条件下生长晶体的第二相夹杂缺陷形态
Figure 4. Second phase inclusion defects in CdZnTe with different temperature of the crucible top t3(Cd partial pressure)
图 5 第二相夹杂缺陷数量随空腔温度t3（Cd分压）的变化关系
Figure 5. Relationship between second phase inclusion defects in CdZnTe and temperature of the crucible top t3(Cd partial pressure)
图 6 温度t3为750℃条件下制备的10批次碲锌镉晶体的第二相夹杂缺陷特征
Figure 6. Second phase inclusion defects in CdZnTe, 10 lots of run-to-run growth and post-annealing with t3=750℃
图 7 温度t3为750℃条件下制备的10批次碲锌镉晶体的第二相夹杂缺陷粒度（尺寸）和密度
Figure 7. The density and the size of second phase inclusion defects in CdZnTe, 10 lots of run-to-run growth and post-annealing with t3=750℃
图 8 两类工艺生长的碲锌镉晶体第二相夹杂缺陷对比情况：(a) 常规（未含退火工艺）生长的碲锌镉晶体第二相夹杂缺陷；(b) 含退火工艺生长的碲锌镉晶体第二相夹杂缺陷
Figure 8. Second phase inclusion defects in CdZnTe: without in-situ post-annealing (a) CdZnTe with post-annealing process(b)
图 9 两种工艺条件下生长晶体的形貌和EPD情况：(a) 常规（未含退火工艺）生长的碲锌镉晶体形貌；(b) 含退火工艺生长的碲锌镉晶体形貌；(c) 常规（未含退火工艺）生长的晶体典型（图 10中的第6批次）EPD~3×104 cm－2，(d) 含退火工艺生长的碲锌镉晶体典型（图 10中的第6批次）EPD~2.2×104 cm－2
Figure 9. 10 lots of run-to-run X-ray diffraction image and EPD results of CdZnTe with/without in-situ post-annealing, CdZnTe without post-annealing process(a)(c), CdZnTe with post-annealing process(b)(d)
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