本文關(guān)鍵詞： 熱絲化學(xué)氣相沉積 SiNx H薄膜 光致發(fā)光 鍵合結(jié)構(gòu)　出處：《內(nèi)蒙古師范大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：氮化硅薄膜作為一種重要的功能薄膜材料已經(jīng)成為國內(nèi)外研究的熱點。因其具有良好的絕緣性、致密性、穩(wěn)定性及抗水汽滲透能力,且能夠有效的阻止B、P、Na等雜質(zhì)的擴散,可作為微電子材料和器件的鈍化膜、絕緣層、擴散掩膜。近年來,隨著多孔硅在室溫下強可見光致發(fā)光現(xiàn)象的發(fā)現(xiàn),突破了以往具有間接帶隙的體硅不能有效發(fā)光的禁區(qū),氮化硅薄膜的又一種應(yīng)用被人們所認識。目前,已經(jīng)有大量的研究報道,納米Si團簇包埋于氧化硅或氮化硅中可以獲得穩(wěn)定而有效的發(fā)光。作為包埋母體材料,氧化硅帶隙較寬,為9.0eV, 氮化硅的帶隙為5.4eV,遂穿勢壘較低,更有利于載流子的注入,是納米硅團簇最為優(yōu)良的包埋母體材料。當(dāng)前富硅氮化硅是硅量子點形成的必要條件,而富硅氮化硅薄膜的制備方法有很多,常見的有低壓化學(xué)氣相沉積法(LPCVD)、等離子化學(xué)氣相沉積法(PECVD)以及磁控濺射法等多種制備手段并加以退火處理。熱絲化學(xué)氣相沉積技術(shù)(HWCVD)是一門較新的沉積技術(shù),目前被廣泛用于微晶硅與多晶硅薄膜的研究,但卻很少見于氮化硅薄膜的制備。熱絲化學(xué)氣相沉積法具有較低的襯底溫度,沉積速率高,易于結(jié)晶并且對薄膜不具有離子轟擊作用等特點,使得該技術(shù)硅量子點的制備也存在較大的前景。本文采用熱絲氣相沉積技術(shù)來制備富硅氮化硅薄膜,氣源采用N2、SiH4以及N2、SiH4和H2的組合做出了三組實驗數(shù)據(jù),研究N2流量以及NH3流量、熱絲溫度對富硅氮化硅的性能的影響。其主要研究結(jié)論如下：(1)采用N2和SiH4作為反應(yīng)氣源時,發(fā)現(xiàn)N2不易在熱絲化學(xué)氣相反應(yīng)中分解,制備樣品含氮量不高,薄膜主要以非晶硅形式存在,樣品容易被氧化,缺陷態(tài)多,薄膜質(zhì)量差。(2)采用NH3、SiH4和H2作為反應(yīng)氣源,調(diào)整NH3與SiH4比例觀察薄膜的特性的變化。隨著氣體比例的提高,薄膜帶隙也發(fā)生緩慢展寬,充分發(fā)揮熱絲優(yōu)點,實現(xiàn)薄膜從富硅到富氮的良好控制。同時,隨N原子的增多,薄膜有序度不斷增大,折射率不斷減小且變化明顯。紅外透射譜顯示：Si-N鍵、N-H鍵隨其流量增大而增大,而Si-H鍵恰好相反。隨N原子的增加缺陷態(tài)明顯增多。(3)采用NH3、Si H4和H2作為反應(yīng)氣源,發(fā)現(xiàn)熱絲溫度對薄膜內(nèi)的N、H含量有明顯的影響,且非單調(diào)性變化,主要歸咎于不同氣體分解溫度。掃描電鏡觀測發(fā)現(xiàn)1500℃時薄膜中出現(xiàn)大小約為1.5um的硅晶粒,分析出氫含量的多少直接影響薄膜結(jié)晶效果。
[Abstract]:Silicon nitride thin film, as an important functional thin film material, has become a hot research topic at home and abroad. Because of its good insulation, compactness, stability and water vapor permeability, it can effectively prevent the diffusion of impurities such as BPN, Na and so on. It can be used as passivation film, insulating layer and diffusion mask for microelectronic materials and devices. In recent years, with the discovery of strong visible photoluminescence phenomena in porous silicon at room temperature, it has broken through the forbidden zone where bulk silicon with indirect band gap can not effectively emit light in the past. Another application of silicon nitride thin films has been recognized. At present, there have been a lot of research reports that nanocrystalline Si clusters embedded in silicon oxide or silicon nitride can obtain stable and effective luminescence. The band gap of silicon oxide is 9.0eV, the band gap of silicon nitride is 5.4 EV, and the barrier of penetration is lower, which is more favorable to carrier injection and is the best embedded parent material of silicon nanoclusters. Silicon nitride rich silicon nitride is a necessary condition for the formation of silicon quantum dots. And there are a lot of ways to prepare silicon nitride films, The common methods are low pressure chemical vapor deposition (LPCVD), plasma chemical vapor deposition (PECVD), magnetron sputtering and annealing. Hot filament chemical vapor deposition (HWCVD) is a new deposition technology. At present, it has been widely used in the study of microcrystalline silicon and polycrystalline silicon films, but rarely in the preparation of silicon nitride thin films. The hot filament chemical vapor deposition method has low substrate temperature and high deposition rate. It is easy to crystallize and has no ion bombardment, which makes the preparation of silicon quantum dots have great prospects. In this paper, silicon nitride thin films are prepared by hot filament vapor deposition. Three groups of experimental data were made by using the combination of N2SiH4, N2OSiH4 and H2 to study the effects of flow rate of N2, flow rate of NH3 and temperature of hot filament on the performance of silicon nitride rich silicon nitride. The main conclusions are as follows: 1) when N 2 and SiH4 are used as reaction gas source, It is found that N _ 2 is not easily decomposed in the chemical gas phase reaction of hot filament, the nitrogen content of the prepared sample is not high, the film mainly exists in the form of amorphous silicon, the sample is easy to be oxidized, the film has many defects, and the film mass is poor. (2) NH _ 3O _ 3SiH _ 4 and H _ 2 are used as the reaction gas source. Adjusting the ratio of NH3 to SiH4 to observe the change of the film characteristics. With the increase of the gas ratio, the band gap of the film also develops slowly, giving full play to the advantages of hot filament, and realizing the good control of the film from silicon to nitrogen. At the same time, with the increase of N atoms, The order degree of the film is increasing, the refractive index is decreasing and the change is obvious. The infrared transmission spectrum shows that the N-H bond increases with the increase of the flow rate of the Si-N bond. However, the Si-H bond is opposite. With the increase of N atom, the defect states increase obviously. (3) NH _ 3Si _ 4 and H _ 2 are used as reaction gas sources. It is found that the temperature of hot filament has a significant effect on the content of Na-H in the film, and the change is not monotonic. Scanning electron microscopy (SEM) showed that silicon grains of about 1.5 um were found in the films at 1500 鈩，

本文編號：1528534