透過電容及蕭特基接面量測電荷載子分布

Abstract

半導體中的電荷載子，包括自由電荷載子、摻雜物、空缺和其他帶電缺陷，在影響半導體器件的性能和功能方面發揮著關鍵作用。獲取電荷載子濃度分佈對於許多應用至關重要，包括元件性能分析、設計優化、製程控制、缺陷分析以及模擬半導體在各種運行條件下的行為。儘管其居有相當的重要性，準確獲得電荷載子濃度分佈存在相當大的挑戰性，其原因源自於檢測和識別不同類型電荷載子的複雜性，例如電子、電洞、摻雜物和結構性帶電位。 本研究引入了一種新穎的方法，該方法結合了實驗和模擬技術，提供了在電流傳導條件下半導體中電荷載子濃度的詳細信息。研究的系統為考慮電子、電洞與摻雜物的蕭特基接面元件，並期望能更進一步擴展到涵蓋更多種類的電荷載子類型。實驗裝置的設計為於半導體兩側製造蕭特基接面與歐姆接面，以建立一個電流垂直通過平面之系統，並對蕭特基接面附近空間電荷區進行電容測量，以計算該區域的總電荷。 模擬通過求解包括泊松方程和漂移-擴散方程在內的常微分方程組來確定空間電荷區內的電荷載子分佈。通過計算取得的電位分佈和電荷載子濃度分佈與實驗電容測量值高度匹配，驗證了模擬條件的合理性。 本研究所提出的方法為剖析半導體中的電荷載子提供了一種有前景的方法，克服了檢測結構性帶電缺陷以及分析不同電荷載子貢獻之限制。研究中展示的電容量測提供了一條探討電荷載子的新途徑，以期能夠更全面的理解半導體中的電荷動態。

Charged species in semiconductors, including free charge carriers, dopants, vacancies, and other charged defects, play a critical role in influencing the performance and functionality of semiconductor devices. Obtaining the charge carrier concentration profile is essential for numerous applications, including component performance analysis, design optimization, process control, defect analysis, and simulating semiconductor behavior under various operating conditions. Despite its importance, achieving an accurate charge carrier concentration profile presents significant challenges due to the complexity of detecting and identifying different types of charge carriers, such as electrons, holes, dopants, and structurally charged sites. This study introduces a novel method that integrates both experimental and simulation techniques to provide detailed information on charge carrier concentrations in semiconductors under current-carrying conditions. The research focuses on a Schottky junction device involving electrons, holes, and dopants, with the aim of extending the study to encompass a broader range of charge carrier types. The experimental setup involved depositing a Schottky junction and an Ohmic junction onto a semiconductor to create a through-plane structure device. Capacitance measurements of the space charge region near the Schottky junction interface, which are influenced by the depletion of free charge carriers, were used to calculate the total charge in this region. Simulations were conducted to determine the charge carrier distribution within the space charge region by solving simultaneous ordinary differential equations, including Poisson’s equation and the drift-diffusion equation. The calculated electric potential profile and charge carrier concentration profile closely matched the experimental capacitance measurements, confirming the accuracy of the simulation conditions. The proposed method offers a promising approach for profiling charge carriers in semiconductors, overcoming limitations related to detecting structurally charged defects and isolating the contributions of different charge species. Capacitance spectroscopy, as demonstrated in this study, provides a new pathway for characterizing charge species, paving the way for a more comprehensive understanding of charge dynamics in semiconductors in the near future.