p-i-n結構之鍺錫元件電流特性

Abstract

近幾年，在關於四族的光電元件中，如操作在近紅外光波段的光偵測器和光發射器，以鍺錫為基底的p-i-n二極體引起了許多人極大的研究興趣，許多關於光特性的研究，如光的吸收及發射，已經完成了。然而進一步了解電性是很重要的。對於光吸收端來說，最重要的參數就是暗電流，光響應以及頻寬，在這篇文章中我們著重在討論暗電流的部分，因為暗電流會增加積體電路光電接收端能量的消耗,跟訊號雜訊比(SNR)。 但是，在實際上鍺錫二極體關於電流電壓的討論是十分複雜的，舉例來說，當金屬/半導體接觸的時候有能量位障存在於異質表面，因此，更深入的探討關於載子的行為以及傳輸是很必要的。在這裡，我們將會描述兩個都是由MBE所成長但結構不同的鍺錫p-i-n二極體，N924和N935，接著會詳細的分析從實驗上得到關於電性的數據。

In recent years, GeSn-based p-i-n diodes have attracted great research attention on group IV opto-electronics such as photodetectors and emitters operated at near infrared wavelengths. Lots of efforts have been done to obtain the photo-electronic properties such as light absorption or emission. However, to further understand the electrical characteristics is needed. For optical receivers the critical photodiode parameters are dark current, responsivity, and bandwidth. In this paper, we will focus on dark current which may increase the power consumption and degrade the signal-to-noise-ratio (SNR) of the integrated optical receivers. However, for a practical GeSn-based diode, the I-V analysis is complicated, for example, the potential barriers at the hetero-interface as well as at the metal/semiconductor contact. Therefore, deeper investigation on the carrier transport and behaviors is needed. In this paper, we will report on two different GeSn-based p-i-n diodes, N924 and N935, which fabricated by MBE, then briefly analysis the result of electrical characteristics from our measurements.