【摘要】：作為集成電路的基礎(chǔ)材料,直拉單晶硅的機(jī)械強(qiáng)度一直得到研究者關(guān)注。隨著集成電路制造的光刻精度的提高,硅片的機(jī)械強(qiáng)度顯得尤為重要。在很大程度上,位錯在應(yīng)力驅(qū)動下的滑移反映了硅片的機(jī)械強(qiáng)度。近十年來,共聚焦顯微拉曼術(shù)已變得很成熟,而單晶硅具有特征的拉曼峰,其峰位對應(yīng)力相當(dāng)敏感。因此,可以利用共聚焦顯微拉曼術(shù)定量地表征硅片的應(yīng)力及其分布等,這為深入地研究單晶硅中的位錯滑移與應(yīng)力之間的關(guān)系提供了有利條件。本文利用共聚焦顯微拉曼術(shù)研究了維氏壓痕的殘余應(yīng)力與對位錯滑移的影響,得到如下主要結(jié)果：(1)研究了不同濃度硼摻雜的直拉單晶硅片上維氏壓痕位錯的滑移行為,采用共聚焦顯微拉曼術(shù)研究了壓痕附近的應(yīng)力分布情況。結(jié)果表明：隨著摻硼濃度的提高,壓痕附近的殘余應(yīng)力明顯變小。此外,在經(jīng)過900℃/2h的熱處理后,電阻率為～1mΩ·cm的硅片上的壓痕位錯沒有發(fā)生明顯的滑移,而電阻率為～10mΩ·cm的硅片上的壓痕位錯則有較顯著的滑移。這是由于高濃度的硼雜質(zhì)對位錯產(chǎn)生了明顯的釘扎作用,從而抑制了位錯的滑移。(2)研究了重?fù)胶洼p摻硼直拉單晶硅片壓痕殘余應(yīng)力和位錯滑移之間的關(guān)系,探討了維氏壓痕附近應(yīng)力在熱處理時釋放的原因。結(jié)果表明：壓痕在進(jìn)行900℃高溫?zé)崽幚頃r,其附近殘余應(yīng)力的釋放主要有兩個原因：在熱處理的前幾分鐘,其應(yīng)力釋放主要由于壓痕殘余的彈性形變的釋放所致,此時壓痕的殘余應(yīng)力急劇降低；在之后,位錯的滑移是壓痕附近殘余應(yīng)力變小的主要原因：殘余應(yīng)力隨著位錯的滑移而逐漸變小,如位錯沒有產(chǎn)生滑移,則殘余應(yīng)力保持不變。(3)采用共聚焦顯微拉曼術(shù)研究了直拉單晶硅片上壓痕的殘余應(yīng)力經(jīng)過300℃或500℃熱處理后的預(yù)釋放,然后研究了應(yīng)力預(yù)釋放對壓痕位錯在后續(xù)較高溫度(700℃-900℃)熱處理過程中滑移的影響。結(jié)果表明：經(jīng)過應(yīng)力預(yù)釋放后,壓痕位錯的滑移速率顯著變小,后續(xù)熱處理溫度越低,滑移速率的減小幅度越大。但是,只要足夠地延長后續(xù)熱處理的時間,位錯滑移的最大距離仍與未經(jīng)預(yù)應(yīng)力釋放情形時的一樣。因此,可以認(rèn)為：在壓痕的殘余應(yīng)力大于位錯在某一溫度滑移所需臨界應(yīng)力的前提下,壓痕位錯在某一溫度滑移的最大距離與應(yīng)力大小無關(guān),只不過達(dá)到最大距離所需的時間隨應(yīng)力的減小而顯著增長。
[Abstract]:As the basic material of integrated circuit, the mechanical strength of Czochralski silicon has been concerned by researchers all the time. With the improvement of lithography precision, the mechanical strength of silicon wafer becomes more and more important. To a large extent, the slip of dislocation driven by stress reflects the mechanical strength of silicon wafer. In recent ten years, confocal Raman microscopy has become very mature, while monocrystalline silicon has a characteristic Raman peak, and its peak position is very sensitive to stress. Therefore, confocal Raman microscopy can be used to quantitatively characterize the stress and distribution of silicon wafers, which provides a favorable condition for further study of the relationship between dislocation slip and stress in monocrystalline silicon. In this paper, the residual stress of Vickers indentation and its effect on dislocation slip are studied by confocal Raman microscopy. The main results are as follows: (1) the slip behavior of Vickers indentation dislocation on Czochralski silicon wafer with different concentrations of boron doping is studied. The stress distribution near indentation was studied by confocal Raman microscopy. The results show that the residual stress near the indentation decreases obviously with the increase of boron concentration. In addition, after heat treatment at 900 鈩，

本文編號：2384002