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利用体晶 CdTe 衬底外延 HgCdTe 有某些局限性,例如晶片大小、易碎性及均匀性,都对外延生长 HgCdTe 有影响,因此研制出一种 CdTe 的代用衬底。本文就介绍这种 CdTe/蓝宝石混合衬底的合成方法及其某些特性,并介绍在这种衬底上液相外延(LPE)生长 HgCdTe 薄膜和器件的特性。与用 CdTe 衬底生长 HgCd-Te 制作的器件相比,在 CdTe/蓝宝石上 LPE 生长的 HgCdTe 薄膜制作的器件,在低温中波红外(MWIR)焦平面上有极好的电学和光学性质,而且二极管间的 D也极为一致。二极管的电阻与面积乘积的典型值,在195K(截止波长λ_c=4.2μm)时为≥10Ωcm~2;在120K(λ_c=4.45μm)时为≥3×10~4Ωcm~2,在77K(λ_c=4.6μ-m)时为≥1×10~6Ωcm~2。不加增透膜其典型量子效率为60—80%。对1024元 MW-IR 混合焦平面阵列的探测度进行分析表明:即使在小量到中等光子背景(高的光子背景是10~(12)光子 cm~(-2)s~(-1)条件下,不合格元件的数量不到5%。
HgCdTe epitaxy using bulk CdTe substrate has some limitations, such as wafer size, friability and uniformity, all affect the epitaxial growth of HgCdTe, so we developed a substitute substrate of CdTe. This article describes the synthesis of CdTe / sapphire hybrid substrates and some of their properties, and describes the growth of HgCdTe films and devices on this substrate by liquid phase epitaxy (LPE). Devices fabricated on LPG-grown HgCdTe films on CdTe / sapphire have superior electrical and optical properties at cryogenic mid-infrared (MWIR) focal planes compared to devices fabricated from CdTe-grown HgCd-Te D between the diode is also very consistent. The typical value of the product of the diode resistance and area is ≧ 10 Ωcm -2 at 195 K (cut-off wavelength λ_c = 4.2 μm), ≧ 3 × 10 -4 Ωcm-2 at 120 K (λ_c = 4.45 μm) = 4.6μ-m) is ≥1 × 10 ~ 6Ωcm ~ 2. The typical quantum efficiency without antireflective coating is 60-80%. The analysis of the detection of a 1024-MW MW-IR hybrid focal plane array shows that even at small to medium photon background (high photon background is 10 ~ (12) photon cm ~ (-2) s ~ (-1) Under, the number of failed components is less than 5%.