Five-dimensional alloy growth of AlInGaNAs and fundamental investigation for realizing Opto-Electronic Integurated Circuits

从去年开始，我们开始了在Si衬底上使用InN/Si、InNAs/Si、InGaNAs/Si等氮化半导体进行2维、3维和4维合金薄膜生长的基础研究，为获得高薄膜质量的AlGaInAsN/Si的5维合金生长进行了初步研究，并明确了晶体生长的一些问题。因此，含In的氮化半导体在高温下根本不可能生长，薄膜质量随着In浓度的增加而急剧下降。此外，还发现InN的带隙能（0.7 eV）比长期以来普遍认为的值（1.9 eV）窄。研究含In在内的氮化半导体的五维合金生长，有必要考虑InN修正能带能的影响。今年，我们研究了氮化半导体（包括In和In）合金生长的窄带隙能量变化的原因。更多的研究了未来使用氮化半导体实现光电集成电路（OEIC）的新材料的可能性。此外，我们尝试在除Si外的GaAs上生长InN和GaN薄膜作为OEIC的衬底，并研究了最佳生长条件。通常，六边形gan和-InN晶体是在立方si和-GaAs衬底上得到的。然而，当在500-600℃的低温下直接生长时，我们发现在这些衬底上可以生长出具有相同晶体结构的高薄膜质量的单立方gan和-InN。这表明OEIC在未来实现的可能性很大。从InN薄膜的退火实验中，我们发现可以通过在生长过程中施加衬底电压来控制薄膜中的氧浓度，从而成功地控制了InN的带隙能量。虽然必须考虑薄膜中氧杂质的影响，但其原因并不总是薄膜中形成具有宽带隙能量的In2O3晶粒。我们提出了氧对氮化半导体五维合金生长的积极影响，以实现OEIC。少

Since last year, we have started fundamental investigation of 2-,3- and 4-dimensional alloy film growth on Si substrates using nitride semiconductors including In such as InN/Si, InNAs/Si, InGaNAs/Si as a preliminary research for obtaining 5-dimensional alloy growth of AlGaInAsN/Si with high film quality, and clarified some problems on crystal growth. As a result, it is fundamentally impossible to grow nitride semiconductors including In at high temperatures and the film quality abruptly degraded with an increase of In concentration. Furthermore, it was found that InN has a band-gap energy (0.7 eV) narrower than the value (1.9 eV) have been generally believed for long time. It is necessary to take the effect of the revised band-gap energy of InN into consideration for researching 5-dimensional alloy growth of nitride semiconductors including In. This year, we have investigated the cause of change into narrow band-gap energy for alloy growth of nitride semiconductors including In and in … More vestigated the possibility of new material using' nitride semiconductors for realization of optical electrical integrated circuits (OEIC) in the future. Furthermore, we tried to grow the InN and GaN films on GaAs besides Si as a substrate for OEIC and investigated the optimum growth conditions. It is usually known that hexagonal-GaN and -InN crystals were obtained on cubic-Si and -GaAs substrates. However, when being grown directly at low temperatures such as 500-600 oC, we found that single cubic-GaN and -InN with high film quality could be grown on these substrates with the same crystal structure. It indicates the high possibility of realization of OEIC in the future. From annealing experiments of InN films, we found that it was possible to control oxygen concentration in the film by applying the substrate voltage during growth and, as a result, we succeed in controlling the band-gap energy of InN. The cause is not always the formation of In2O3 crystal grains with wide band-gap energy in the film although the effect of oxygen impurities in the film must be considered. We submit the positive influence of oxygen in the 5-dimensional alloy growth of nitride semiconductors for realization of OEIC. Less