【摘要】：金剛石薄膜的生長(zhǎng)分為形核和生長(zhǎng)兩個(gè)階段,襯底溫度、沉積壓強(qiáng)、碳?xì)錃怏w的流量以及襯底偏壓等工藝參數(shù)直接影響著金剛石薄膜的形核階段,從而對(duì)金剛石薄膜的表面結(jié)構(gòu)以及晶體晶向產(chǎn)生影響,因此將金剛石薄膜生長(zhǎng)的工藝參數(shù)作為薄膜制備的重要研究對(duì)象。本文采用熱絲化學(xué)氣相沉積(HFCVD)的方法在單面為碳面的碳化硅襯底成功制備了金剛石薄膜。研究了各種工藝參數(shù)對(duì)金剛石薄膜的影響,討論了它們作用的機(jī)理,優(yōu)化了工藝參數(shù),得出結(jié)論如下:1.襯底的預(yù)處理能夠極大的改善碳化硅襯底表面的微結(jié)構(gòu),從而對(duì)金剛石薄膜的連續(xù)性生長(zhǎng)產(chǎn)生影響。在機(jī)械研磨以及化學(xué)清洗的預(yù)處理方法下,碳化硅表面生長(zhǎng)的金剛石顆粒少、薄膜連續(xù)性差且有薄膜脫落的現(xiàn)象;在超聲清洗預(yù)處理方法下,金剛石顆粒尺寸大小不一,薄膜均勻性較差;在研磨加超聲清洗的預(yù)處理方法下,金剛石薄膜致密度高、薄膜連續(xù)性最好。2.氫氣流量的大小與金剛石薄膜的表面形貌和晶體晶向有著密切的關(guān)系。當(dāng)氫氣流量較低的時(shí)候150 mL/min,氫氣的不充足會(huì)造成碳?xì)浠钚曰鶊F(tuán)不充足,造成生長(zhǎng)金剛石薄膜反應(yīng)過(guò)慢,從而導(dǎo)致金剛石薄膜難以形成。當(dāng)氫氣的流量較高的時(shí)候200 mL/min,較低的氫氣流量有利于(111)面的生長(zhǎng)。除此之外,由于氫氣流量較低,氫氣對(duì)石墨的刻蝕不足,從而導(dǎo)致樣品出現(xiàn)石墨,造成金剛石薄膜不純。在氫氣流量為250 mL/min情況下,氫氣充足有利于(100)面的生長(zhǎng)。3.襯底溫度以及沉積氣壓影響金剛石薄膜的形核速率。隨著溫度(或沉積氣壓)的提高,金剛石薄膜的形成速率是提升的。襯底溫度過(guò)高或沉積氣壓過(guò)大都會(huì)造成金剛石二次形核出現(xiàn),破壞金剛石薄膜表面完整性;襯底溫度過(guò)低或沉積氣壓過(guò)小,碳?xì)浠鶊F(tuán)反應(yīng)速率慢,金剛石薄膜生長(zhǎng)速率慢。4.襯底偏壓提高碳?xì)潆x子活性,加快碳?xì)浠鶊F(tuán)活性反應(yīng)速率。氣壓影響真空室內(nèi)活性基團(tuán)的碰撞速率,從而對(duì)金剛石薄膜生長(zhǎng)速率產(chǎn)生影響。隨著襯底偏壓的增大,金剛石薄膜生長(zhǎng)速率更快。但是過(guò)壓對(duì)金剛石薄膜設(shè)備負(fù)荷較大,并且對(duì)金剛石薄膜的生長(zhǎng)速率提升不明顯,因此將700 V作為金剛石薄膜生長(zhǎng)的偏壓。
[Abstract]:The growth of diamond films is divided into two stages: nucleation and growth. The process parameters, such as substrate temperature, deposition pressure, flow rate of hydrocarbon gas and substrate bias, directly affect the nucleation stage of diamond films. As a result, the surface structure and crystal orientation of diamond film are affected. Therefore, the technological parameters of diamond film growth are regarded as an important research object in the preparation of diamond thin film. Diamond thin films were successfully deposited on sic substrate with carbon surface by hot filament chemical vapor deposition (HFCVD). The effects of various process parameters on diamond films were studied, the mechanism of their action was discussed, and the process parameters were optimized. The conclusions are as follows: 1. The pretreatment of the substrate can greatly improve the microstructure of the silicon carbide substrate surface, thus affecting the continuous growth of diamond films. Under the pre-treatment of mechanical grinding and chemical cleaning, the diamond particles grown on the surface of silicon carbide are few, the continuity of the film is poor, and there is a phenomenon of film shedding. Under the pretreatment method of ultrasonic cleaning, the size of diamond particles is different and the film uniformity is poor, and under the pretreatment method of grinding and ultrasonic cleaning, the density of diamond film is high and the continuity of the film is the best. The hydrogen flow rate is closely related to the surface morphology and crystal orientation of diamond films. When the flow rate of hydrogen is low, the insufficient hydrogen of 150 mL/min, will lead to insufficient active groups of carbon and hydrogen, which will cause the reaction of diamond film to be too slow, so that it is difficult to form diamond film. When the flow rate of hydrogen is higher, the lower flow rate of hydrogen at 200 mL/min, is beneficial to the growth of (111) surface. In addition, due to the low flow rate of hydrogen, the etching of graphite by hydrogen is insufficient, which leads to the appearance of graphite and impure diamond film. At a hydrogen flow rate of 250 mL/min, sufficient hydrogen is conducive to the growth of (100) surfaces. 3. The nucleation rate of diamond films is influenced by substrate temperature and deposition pressure. With the increase of temperature (or deposition pressure), the formation rate of diamond films is increased. If the substrate temperature is too high or the deposition pressure is too high, the secondary nucleation of diamond will occur, and the surface integrity of diamond film will be destroyed, the substrate temperature is too low or the deposition pressure is too small, the reaction rate of carbon and hydrogen groups is slow, and the growth rate of diamond film is slow. Substrate bias increases the activity of hydrocarbon ions and accelerates the reaction rate of hydrocarbon groups. Air pressure affects the collision rate of active groups in vacuum chamber, thus affects the growth rate of diamond films. With the increase of substrate bias, the growth rate of diamond films is faster. However, the overvoltage has a large load on the diamond film equipment, and the growth rate of the diamond film is not significantly increased, so 700 V is used as the bias voltage for the growth of diamond film.
【學(xué)位授予單位】：河北工業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TB383.2;TQ163

【參考文獻(xiàn)】

相關(guān)期刊論文 前1條

1 左偉;沈彬;孫方宏;陳明;;熱絲化學(xué)氣相法生長(zhǎng)單晶金剛石顆粒的襯底溫度場(chǎng)仿真及實(shí)驗(yàn)研究(英文)[J];人工晶體學(xué)報(bào);2007年05期

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本文編號(hào)：2463104