鍺基紅外光偵測器應用於光連接系統之設計與建模

Abstract

在取代積體電路銅導線的光連接傳輸系統中，紅外光偵測器是光學訊號接收端的重要元件，其中，鍺的能隙(0.66 eV) 使得鍺基元件能夠有效吸收紅外光訊號，鍺基紅外光偵測器近年來成為許多研究的題目。文獻指出，鍺基紅外光偵測器的主要缺點是暗電流過高，造成訊號干擾以及額外功率消耗。本篇論文以水平P-i-N 結構的鍺基紅外光偵測器為研究對象，首先透過變溫量測與分析，得知在室溫以及小偏壓操作下，暗電流來自於Shockley-Read-Hall 載子產生過程 (SRH generation)。接著利用TCAD 模擬軟體，取用上述SRH 模型，模擬不同幾何參數對於偵測器之暗電流、光電流以及傳輸速度的影響，探討各參數的權衡與最佳化，為未來提供製造低雜訊、高效率以及高頻寬的鍺基紅外光偵測器的方針。

As one of the crucial components in optical interconnect system, germanium photodiodes (GePD) are promising due to its corresponding bandgap (0.66 eV) to absorb infra‐red light and the compatibility to silicon‐based photonics and electronics. However, many researchers have shown that the key issue of GePD is high dark current, and efforts were done to suppress the dark current and to increase gain‐bandwidth product by improving GePD efficiency and speed. This thesis aims to systematically find the photo‐electrical behavior based on the simplest P‐i‐N germanium photodiodes. To investigate the main physical mechanism behind the dark current of germanium photodiode, analysis of temperature dependence ofexperimentally measured dark current is performed. After that, several guidelines toward the GePD structure are provided in this thesis with the aid of TCAD simulation, which can be a useful reference when fabricating high‐efficiency and low‐power consumption germanium photodetector with lateral P‐i‐N structure.