Passivation of dislocations in GaAs-on-Si

详细研究了PH_3/H_2等离子体钝化对硅衬底生长的砷化镓的影响。结果表明，PH_3/H_2等离子体暴露可同时实现表面磷化和氢化，减少等离子体损伤。在PH_3/H_2等离子体照射下，由于氢和磷原子的掺入使体缺陷和表面缺陷相关的非辐射复合中心钝化，从而有效地改善了Si上GaAs的光学和电学性能。实验结果表明，PH_3/H_2等离子体暴露降低了AlGaAs/GaAs的复合速率，提高了少数载流子寿命。PH_3/H_2等离子体暴露在Si上的GaAs Schottky二极管的反向击穿电压提高了约1.6倍，在Si上生长的钝化GaAs太阳能电池的转换效率比在Si上生长的样品提高了15.9%至18.6%。钝化后的GaAs在Si上表现出优异的热稳定性，这可能是由于H和P原子积极参与了PH_3/H_2等离子体钝化过程。发现在PH_3/H_2等离子体暴露过程中，GaAs/Si异质外延层中高密度的位错极大地促进了磷原子的扩散。电子束诱导电流证明，在纯H_2等离子体中加入P能有效地降低缺陷相关的暗斑密度。此外，PH_3/H_2等离子体暴露大大提高了Si衬底上生长的GaAs pn结结构的少数载流子性能，降低了饱和电流。掺入的P原子强烈钝化了GaAs/Si太阳能电池中残位错的电态。氢等离子体钝化的AlGaAs/GaAs多量子阱样品在腔模式下观察到明显的自发发射增强。这是由于缺陷相关的非辐射深中心的电活动钝化和少数载流子寿命增加所致。在没有PH_3/H_2等离子体暴露使表面磷解离的情况下，在Si衬底上生长的InGaP实现了缺陷钝化。观察到光致发光强度显著增强，这是由于氢化缺陷相关的非辐射重组中心。少

Effects of PH_3/H_2 plasma passivation of GaAs grown on Si substrate have been investigated in detail. It is observed that both the surface phosphidation and hydrogenation can be realized simultaneously with a reduced plasma-induced damage by using PH_3/H_2 plasma exposure. The optical and electrical properties of GaAs on Si are effectively improved by PH_3/H_2 plasma exposure due to the passivation of bulk and surface defects-related nonradiative recombination centers by incorporation of hydrogen and phosphorous atoms. The experimental results show that the AlGaAs/GaAs recombination rate is reduced and the minority carrier lifetime is improved by the PH_3/H_2 plasma exposure. The PH_3/H_2 plasma exposed GaAs Schottky diodes on Si show an increase in the reverse breakdown voltage by a factor of about 1.6, and the as-passivated GaAs solar cell grown on Si shows an increase in the conversion efficiency from 15.9% to 18.6 % compared to that of the as-grown samples. The passivated GaAs dev … More ices on Si show outstanding thermal stability, which is probably due to the active participation of both H and P atoms in the PH_3/H_2 plasma passivation process. It is found that the high density of dislocations in GaAs/Si heteroepitaxial layers largely enhance the diffusion of phosphorous atoms during the PH_3/H_2 plasma exposure. Electron beam-induced current proved that the defect-related dark spot density was effectively reduced by adding P into the pure H_2 plasma In addition, PH_3/H_2 plasma exposure greatly increased the minority carrier properties and decreased the saturation current of GaAs pn junction structure grown on Si substrate. The incorporated P atoms strongly passivated the electrical states of residual dislocations in GaAs/Si solar cell. Significant spontaneous emission enhancement is observed at the cavity mode for the hydrogen plasma passivated AlGaAs/GaAs multi-quantum well samples., which results from the passivation of electrical activity of defect-related non-radiative deep centers and increased minority carrier lifetime. The defect passivation of InGaP grown on Si substrates was achived without dissociation of phosphorous from the surface by PH_3/H_2 plasma exposure. A significant enhancement of the photoluminescence intensity was observed, which is due to the hydrogenation defect-related nonradiative recombination centers. Less