In situ low temperature As-doping of Ge films using As(SiH3)3 and As(GeH3)3: fundamental properties and device prototypes
In situ low temperature As-doping of Ge films using As(SiH3)3 and As(GeH3)3: fundamental properties and device prototypes
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使用 As(SiH3)3 和 As(GeH3)3 对 Ge 薄膜进行原位低温 As 掺杂：基本特性和器件原型
DOI：
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发表时间：
2015
期刊：
影响因子：
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通讯作者：
J. Kouvetakis
中科院分区：
文献类型：
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作者：
Chi Xu;J. Gallagher;P. Wallace;C. L. Senaratne;P. Sims;J. Menéndez;J. Kouvetakis
我们报告了一种新方法的发展，系统地和可控地实现非常高的载流子浓度的As掺杂的锗使用超低温，高效率的路线的基础上，结构和化学相容的无机砷As（SiH 3）3和As（GeH 3）3。在Ge缓冲的Si（100）上使用具有Ge 3 H8的化合物在330 °C下的原位沉积来生长Ge n层。生长的薄膜被发现表现出优异的结晶度，无缺陷的界面，原子级光滑的表面和平坦的掺杂轮廓与陡峭的边缘。活性载流子密度的测量范围为1 × 1019-8.4 × 1019 cm-3，与前体类型无关。这些载流子密度与二次离子质谱法测量的原子As浓度密切一致，表明生长机制促进了掺杂剂原子的几乎完全的替代掺入，同时抑制了非活性簇和缺陷的形成。尽管As在Ge中的溶解度相对于P的溶解度较低，但用As（SiH 3）3和As（GeH 3）3获得的最大载流子浓度比用类似的P（SiH 3）3和P（GeH 3）3发现的高大约30%。这个结果，沿着的密切相似性，在带隙变窄观察到的两种方法，表明砷掺杂路线可能是有利的光学器件，需要最高可能的载流子浓度，以填充导带谷与直接的间隙发射。另一方面，由于As掺杂Ge中固有的载流子弛豫时间较短，观察到的最低电阻率5 × 10−4 Ω cm略高于P掺杂类似物的最低电阻率。最后，使用As（SiH 3）3和As（GeH 3）3制造的光电二极管的光学响应度，电致发光和I-V特性被发现与从Ge-on-Si参考类似物中观察到的那些相当，这表明这里描述的化学方法代表了一种可行的和直接的途径来掺杂和激活器件质量材料。
We report the development of a new method to systematically and controllably achieve very high carrier concentrations in As-doped germanium using ultra-low temperature, high efficiency routes based on the structurally and chemically compatible inorganic hydrides As(SiH3)3 and As(GeH3)3. The Ge n-layers are grown on Ge-buffered Si(100) using in situ depositions of the compounds with Ge3H8 at 330 °C. The as-grown films are found to exhibit excellent crystallinity, defect-free interfaces, atomically smooth surfaces and flat doping profiles with abrupt edges. The active carrier densities are measured to be in the range of 1 × 1019–8.4 × 1019 cm−3 irrespective of the precursor type. These carrier densities are in close agreement with atomic As concentrations measured by secondary ion mass spectrometry, indicating that the growth mechanism promotes the nearly complete substitutional incorporation of dopant atoms while suppressing the formation of non-active clusters and defects. In spite of the lower solubility of As in Ge relative to that of P, the maximum carrier concentrations obtained with As(SiH3)3 and As(GeH3)3 are roughly 30% higher than those found with the analogous P(SiH3)3 and P(GeH3)3. This result, along with the close similarity in band gap narrowing observed for the two methods, suggests that the As-doping route may be advantageous for optical devices that require the highest possible carrier concentrations to populate the conduction band valley associated with direct gap emission. On the other hand—due to the inherently shorter carrier relaxation times in As-doped Ge—the lowest observed resistivity of 5 × 10−4 Ω cm is slightly higher than the lowest resistivity from P-doped analogs. Finally, optical responsivity, electroluminescence and I–V properties of photodiodes fabricated using As(SiH3)3 and As(GeH3)3 are found to be on par with those observed from Ge-on-Si reference analogs, indicating that the chemistry approach described here represents a viable and straightforward route to doping and activation of device-quality materials.