利用自我對準微接合技術製作矽鍺異質接面波導光偵測器

A novel process using self-aligned microbonding technique to make Ge/Si heterojunction PIN waveguide photodetectors

田仲達(Jhong-Da Tian)

指導教授 ： 李明昌

國立清華大學/電機資訊學院/光電工程研究所/碩士(2012年)

摘要

近年來，矽鍺整合技術應用於電子元件或是光學元件上漸漸受到矚目，舉例來說，利用鍺材料載子遷移率高的特色做主動調變器，或鍺紅外光偵測器，文獻上都已成功做出且有不錯的特性表現。但基於兩種材料本質上4%的晶格常數差異，使矽鍺整合有一定難度。一般常用方法如直接磊晶鍺於矽基板上，但此法需要較特殊的製程處理和儀器，且磊晶後的鍺需要高溫長時間的退火，才能達到元件所需高品質單晶鍺，此高熱預算會降低元件表現，且增加與積體電路整合困難度。另一種達成鍺矽異質結構的方法為晶圓接合法，可直接將鍺晶圓和矽晶圓對接，不需高溫的鍵結，但缺點為太浪費材料，且接合時，晶圓表面輪廓不易控制，此問題將造成元件良率下降。
回顧文獻，使用液相磊晶法可保證所長鍺為高品質單晶，但此法需將鍺先包覆於一非晶材料坩鍋中，高溫退火使鍺成為單晶，而鍺和矽基板被坩鍋絕緣層所阻擋。在本論文中，提出新穎的方法，利用自我對準微接合技術直接將液相磊晶後的鍺材料和矽基板鍵結，不需高溫長時間退火，且接合範圍小，改善大範圍晶圓接合問題，並實際完成鍺矽異質接面PIN波導型光偵測器，所量測的暗電流密度、光反應、操作速度皆有高水準表現。

關鍵字

鍺矽異質結構 ； 光偵測器

並列摘要

Ge/Si integration receives a lot of attention for both electronic and photonic devices. For example, Ge/Si-based high-mobility transistors and high-speed photodetectors have been demonstrated with superior performances. However, pure Ge grown on Si is critical due to the lattice mismatch (4%) between Si and Ge. Direct epitaxial growth of Ge on Si usually requires special process techniques and tools. In addition, Ge epitaxial growth often requires a high-temperature process condition for an extended period of time to achieve high crystal quality. Nevertheless, the resultant thermal budget could degrade the device properties and complicate the integration with ICs. Another approach for Ge/Si hetero-integration is a direct wafer or die bonding of Ge onto Si wafers. However, removing the bonded substrates could be a waste of material. Furthermore, bonding surface topography often affects the bonding yield very much.
Previously, rapid melt growth (RMG) of Ge on insulator showed a promising way for the integration of high-quality Ge with ICs. However, through this process, a Ge/Si heterojunction can’t be made since the Ge layer has to be separated from the Si surface by a dielectric. In this paper, a novel process using a self-aligned microbonding technique to directly make the RMG Ge strips contacted on SOI waveguides. A microbonded Ge/Si PIN waveguide photodetector is demonstrated with good performance in dark current, operation bandwidth, and responsivity.

並列關鍵字

Ge/Si ； photodetector ； PIN

參考文獻

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