Spin-on doping of germanium-on-insulator wafers for monolithic light sources on silicon
Spin-on doping of germanium-on-insulator wafers for monolithic light sources on silicon
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DOI：
10.7567/jjap.54.052101
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发表时间：
2015-05-01
影响因子：
1.5
通讯作者：
Saito, Shinichi
中科院分区：
文献类型：
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作者：
Al-Attili, Abdelrahman Z.;Kako, Satoshi;Saito, Shinichi
高电子掺杂锗(Ge)被认为是将Ge转化为光增益材料、实现单片光源集成在硅片上的重要过程。自旋掺杂是一种在不影响晶体质量的情况下获得高掺杂浓度的方法，而不是其他方法，如离子注入和材料生长过程中的原位掺杂。然而，目前还没有满足这些要求的标准自旋掺杂配方。在本文中，我们研究了绝缘体上锗(GOI)晶片的自旋掺杂。在自旋掺杂过程中发现了几个问题，特别是Ge与氧化物之间的粘合，激活过程中的表面氧化，以及由于退火在层中产生的应力。为了缓解这些问题，首先通过干法刻蚀Ge盘，然后进行自旋掺杂。即使使用这种方法来降低应力，仍然可以通过光学显微镜成像来识别Ge的局部剥离。然而，在移除玻璃后，大部分GE磁盘仍然存在。根据拉曼数据，我们不能确定线形的展宽，这表明了良好的结晶质量，而应力略有松弛。我们还确定了掺杂样品的光致发光强度随光抽运功率的增加而线性增加，这意味着在伽马谷处有直接的布居和复合。(C)2015年日本应用物理学会
High electron doping of germanium (Ge) is considered to be an important process to convert Ge into an optical gain material and realize a monolithic light source integrated on a silicon chip. Spin-on doping is a method that offers the potential to achieve high doping concentrations without affecting crystalline qualities over other methods such as ion implantation and in-situ doping during material growth. However, a standard spin-on doping recipe satisfying these requirements is not yet available. In this paper we examine spin-on doping of Ge-on-insulator (GOI) wafers. Several issues were identified during the spin-on doping process and specifically the adhesion between Ge and the oxide, surface oxidation during activation, and the stress created in the layers due to annealing. In order to mitigate these problems, Ge disks were first patterned by dry etching followed by spin-on doping. Even by using this method to reduce the stress, local peeling of Ge could still be identified by optical microscope imaging. Nevertheless, most of the Ge disks remained after the removal of the glass. According to the Raman data, we could not identify broadening of the lineshape which shows a good crystalline quality, while the stress is slightly relaxed. We also determined the linear increase of the photoluminescence intensity by increasing the optical pumping power for the doped sample, which implies a direct population and recombination at the gamma valley. (C) 2015 The Japan Society of Applied Physics