Study on Fabrication Technology of GaInAs/InP Device with Ultrafine Structure

我们研究了电子束曝光和有机物气相外延（OMVPE）制备GaInAs/InP超细周期结构。以下是我们的结果摘要。1.我们优化了OMVPE条件，使背景载流子密度低至10^<13>/cm ^3。我们在室温吸收谱中观察到明确的激子峰，异质结处的电子波反射显示出良好的异质界面。2.在抗蚀剂层厚度为40 nm、加速电压为50 KV、显影液稀释、后烘温度降低、后烘周期缩短的条件下，通过电子束曝光，绘制出了40 nm间距的周期图形。3.我们研究了在不引入晶体损伤的情况下将图案转移到半导体晶体表面。通过我们发明的两步湿法化学腐蚀，我们获得了50 nm间距的周期结构，这是世界上最细的周期光刻技术4。作为一种替代的转移方法，我们研究了OMVPE选择性生长技术，以获得70 nm间距的结构。5.研究了反应离子刻蚀转移图形的方法，得到了较好的结果。通过降低加速电压，在垂直刻蚀的样品中保持了较强的光致发光特性。6.我们在较低的生长温度（520 ℃）下通过OMVPE再生长制备了完全嵌入的GaInAs/InP超细周期结构（间距为70 nm，深度为40 nm）。用该技术制备的量子线激光器的激光输出显示出很好的晶体质量，总之，我们实现了在不引入严重损伤的情况下制备GaInAs/InP超细周期结构。进一步减小间距和研究界面性质以提高再生长晶体的质量是下一阶段的重要课题。

We have investigated the electron bean exposure and the organometalic vapor phase epitaxy (OMVPE) to create GaInAs/InP ultrafine periodic structure. The following is a summary of our result. 1. We have optimized the OMVPE condition to attain back ground carrier density as low as 10^<13>/cm^3. We have observed definite exciton peaks in room-temperature absorption spectra, the electron wave reflection at heterojunctions showing excellent heterointerfaces. 2. We have attained to draw 40nm-pitch periodic pattern by the electron beam exposure under condition newly obtained; the resist layer-thickness as thin as 40nm, the acceleration voltage as high as 50 KV, diluted developer and lowered-temperature and reduced-period post baking. 3. We have investigated to transfer the pattern to the surface of the semiconductor crystal without introducing of the crystal damage. By the two-step wet chemical etching invented by us, we have attained 50nm-pitch periodic structures which is the world finest period attained by lithography techniques 4. As an alternative transfer method, we have studied the OMVPE selective growth technique to attain 70nm-pitch structures. 5.We have investigated the reactive ion etching to transfer the pattern to obtain promising results. By reducing the acceleration voltage, a strong photoluminescence property have been preserved in samples etched vertically. 6. We have created completely embedded GaInAs/InP ultrafine(70nm-pitch and 40nm-depth) periodic structures by OMVPE regrowth at a lowered growth temperature(520 C). The lasing of the quantum wire laser fabricated by this technique have shown quite good crystal quality.In short, we have achieved to create GaInAs/InP ultrafine periodic structures without introducing a serious damage. Further reduction in the pitch and a detail study about interface properties to improve the quality of the regrown crystal are very important theme as the next stage.