Zhang Qingfang, Liu Yan, Yan Jing, Zhang Chunfu, Hao Yue, Han Genquan
Opt Express. 2015 Jan 26;23(2):739-46. doi: 10.1364/OE.23.000739.
In this paper, we design a biaxial tensile strained GeSn photodetector with fin structure wrapped in Si(3)N(4) liner stressor. A large biaxial tensile strain is induced in GeSn fins by the expansion of Si(3)N(4) liner stressor. The distribution of tensile strain in GeSn fins was calculated by a finite element simulation. It is observed that magnitude of the strain increases with the reduction of fin thickness T(fin). Under the biaxial tensile strain, the direct band gap E(G,Γ) of GeSn fin photodetector is significantly reduced by lowering Γ conduction valley in energy and lifting of degeneracy of valence bands. As the 30 nm Si(3)N(4) liner stressor expanses by 1%, a E(G,Γ) reduction of ~0.14 eV is achieved in Ge(0.92)Sn(0.08) fins with a T(fin) of 100 nm. The cut-off wavelengths of strained Ge(0.96)Sn(0.04), Ge(0.92)Sn(0.08) and Ge(0.90)Sn(0.10) fin photodetectors with a T(fin) of 100 nm are extended to 2.4, 3.3, and 4 μm, respectively. GeSn fin photodetector integrated with Si(3)N(4) liner stressor provides an effective technique for extending the absorption edge of GeSn with Sn composition less than 10% to mid-infrared wavelength.
在本文中，我们设计了一种具有鳍片结构的双轴拉伸应变锗锡光电探测器，该鳍片结构包裹在Si₃N₄衬里应力层中。Si₃N₄衬里应力层的膨胀在锗锡鳍片中诱导出大的双轴拉伸应变。通过有限元模拟计算了锗锡鳍片中拉伸应变的分布。观察到应变的大小随着鳍片厚度T(fin)的减小而增加。在双轴拉伸应变下，锗锡鳍片光电探测器的直接带隙E(G,Γ)通过降低能量中的Γ导带谷和解除价带简并而显著减小。当30 nm的Si₃N₄衬里应力层膨胀1%时，在鳍片厚度T(fin)为100 nm的Ge₀.₉₂Sn₀.₀₈鳍片中实现了约0.14 eV的E(G,Γ)减小。鳍片厚度T(fin)为100 nm的应变Ge₀.₉₆Sn₀.₀₄、Ge₀.₉₂Sn₀.₀₈和Ge₀.₉₀Sn₀.₁₀鳍片光电探测器的截止波长分别扩展到2.4、3.3和4μm。与Si₃N₄衬里应力层集成的锗锡鳍片光电探测器为将锡成分小于10%的锗锡的吸收边缘扩展到中红外波长提供了一种有效技术。
