Electrical and optical characterisation of low temperature grown InGaAs for photodiode applications
Electrical and optical characterisation of low temperature grown InGaAs for photodiode applications
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DOI：
10.1088/1361-6641/aba167
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发表时间：
2020-09-01
影响因子：
1.9
通讯作者：
Tan, Chee Hing
中科院分区：
文献类型：
--
作者：
Lim, Leh Woon;Patil, Pallavi;Tan, Chee Hing
稀胺和氮化物合金是很有希望用于带隙工程的半导体，为红外光电二极管等器件提供了额外的设计自由。要在III-V半导体中掺入铋或氮，需要较低的生长温度。然而，低生长温度对暗电流和响应度的影响还不是很清楚。在这项工作中，一组InGaAsp-i-n晶片在250,300,400和500℃的恒定温度下生长了所有的p，i和n层。生长第二组晶片，其中p层和n层在500℃生长，而i层在250、300和400℃生长。光电二极管由所有七个晶片制成。当采用恒定生长温度时(对于所有p、i和n层)，我们观察到在500℃下生长的光电二极管在-1V处显示的暗电流密度比在250℃下生长的光电二极管的暗电流密度低6个数量级，而在1520 nm的照明波长下的响应率是250℃下生长的光电二极管的4.5倍。来自第二组晶片的结果表明，通过在高温下生长p层和n层可以恢复性能退化。例如，将光电二极管与在250℃下生长的i层进行比较，光电二极管在-1V时显示出暗电流密度，当p层和n层在500℃下生长时，暗电流密度低五个数量级。生长后，在250℃和300℃下生长的两个晶片上进行的595℃下15分钟的退火显示二极管响应性恢复，但暗电流没有显著改善。我们的工作表明，在高温下生长盖层对于保持响应性和最小化暗电流退化是必要的，这为开发需要较低生长温度的新型光电二极管材料提供了一条途径。本文报告的数据可从ORDA数字存储库获得。
Dilute bismide and nitride alloys are promising semiconductors for bandgap engineering, opening additional design freedom for devices such as infrared photodiodes. Low growth temperatures are required to incorporate bismuth or nitrogen into III-V semiconductors. However, the effects of low growth temperature on dark current and responsivity are not well understood. In this work, a set of InGaAs p-i-n wafers were grown at a constant temperature of 250, 300, 400 and 500 degrees C for all p, i and n layers. A second set of wafers was grown where the p and n layers were grown at 500 degrees C while the i-layers were grown at 250, 300 and 400 degrees C. Photodiodes were fabricated from all seven wafers. When constant growth temperature was employed (for all p, i and n layers), we observed that photodiodes grown at 500 degrees C show dark current density at -1 V that is six orders of magnitude lower while the responsivity at an illumination wavelength of 1520 nm is 4.5 times higher than those from photodiodes grown at 250 degrees C. Results from the second set of wafers suggest that performance degradation can be recovered by growing the p and n layers at high temperature. For instance, comparing photodiodes with i-layers grown at 250 degrees C, photodiodes showed dark current density at -1 V that is five orders of magnitude lower when the p and n layers were grown at 500 degrees C. Postgrowth annealing, at 595 degrees C for 15 min, on the two wafers grown at 250 and 300 degrees C showed recovery of diode responsivity but no significant improvement in the dark current. Our work suggests that growth of the cap layer at high temperature is necessary to maintain the responsivity and minimise the dark current degradation, offering a pathway to developing novel photodiode materials that necessitate low growth temperatures. The data reported in this paper is available from the ORDA digital repository.