本文選題：Ⅲ族氮化物 + N極性��； 參考：《吉林大學》2016年博士論文

【摘要】：Ⅲ族氮化物具有優(yōu)異的光學與電學性質(zhì),現(xiàn)已經(jīng)廣泛應用于發(fā)光二極管(LEDs)、激光器、光電探測器和大功率電子器件中。通常金屬極性Ⅲ族氮化物薄膜具有較高的晶體質(zhì)量,而高質(zhì)量的N極性Ⅲ族氮化物薄膜制備則比較困難,因此大部分器件的應用中都采用了金屬極性Ⅲ族氮化物材料。然而,N極性Ⅲ族氮化物的潛力還沒有被充分挖掘,在增強型晶體管、高度縮放晶體管、光子探測器、太陽電池、齊納隧道二極管等器件的應用中,N極性結(jié)構將比金屬極性結(jié)構更有優(yōu)勢,N極性的結(jié)構也有利于提高LEDs和LDs的性能,如提高載流子的注入效率、減小載流子的溢出以及增加In的組分等,這吸引了很多研究者的興趣。本文在藍寶石襯底上開展了N極性GaN、InGaN和InN薄膜的生長和特性研究,取得的主要成果如下：1.研究了襯底傾斜角、成核層厚度、高溫GaN生長溫度以及Will比對N極性GaN薄膜性質(zhì)的影響。結(jié)果表明,當藍寶石襯底的傾斜角從0.3°增加到0.8。時,N極性GaN的晶體質(zhì)量、光學質(zhì)量以及表面形貌得到了極大的改善,這主要得益于大傾斜角藍寶石襯底增加了表面的臺階密度,同時減小了臺階之間的距離,這增加了Ga吸附原子接觸到臺階和扭折位置的概率,有利于形成臺階流生長模式,從而提高了薄膜的晶體質(zhì)量。成核層的厚度為20 nm時,GaN薄膜的螺位錯與刃位錯密度出現(xiàn)了極小值,即薄膜的晶體質(zhì)量最好。而高溫GaN的生長溫度從1000℃增加到1080℃時,GaN薄膜的“黃帶”發(fā)光顯著降低,說明較高的生長溫度有利于提高N極性GaN薄膜的光學質(zhì)量。在1080℃條件下,當Will比為1500時,N極性GaN薄膜的晶體質(zhì)量最優(yōu),其螺位錯與刃位錯密度分別為4.70×107cm-2和3.13×108cm-2,表面的均方根粗糙度(RMS)值為0.331nm,背景電子濃度和遷移率分別達到了2.35×1017/cm3和509 cm2/V·s,這些性能指標均與Ga極性GaN薄膜的性能相當。2.在N極性GaN模板上生長了N極性InGaN薄膜,研究了生長溫度、Ⅴ/Ⅲ比、三甲基銦(TMIn)流量以及生長壓力對N極性InGaN薄膜性質(zhì)的影響。結(jié)果表明,較低的生長溫度和大TMIn流量是增加薄膜的In組分的最有效的方法,但In組分的增加使InGaN與GaN之間的晶格失配增加,不可避免的降低了InGaN薄膜的晶體質(zhì)量。較高的生長溫度有利于提高N極性InGaN薄膜的晶體質(zhì)量和光學質(zhì)量,在760℃及以上的生長溫度下,薄膜都有較強的近帶邊發(fā)光,而生長溫度低于740℃時,近帶邊發(fā)光減弱,深能級發(fā)光逐漸占主導。由于In的平衡分壓比Ga高很多,存在于氣相中用以維持平衡的In占In的總輸入量的比例較大,因而薄膜中的In組分對TMIn的輸入量更為敏感。N極性InGaN薄膜的表面粗糙度隨生長溫度和壓力的增加而降低。較高的生長壓力有利于抑制In-N鍵的分解,在提高薄膜的晶體質(zhì)量的同時也增加了薄膜中的In組分。3.制備了藍紫光和藍綠光的N極性LED。在樣品的X射線衍射(XRD)2θ-ω掃描譜中可清晰地顯示出高級衛(wèi)星峰,說明N極性LED材料具有較好的晶體質(zhì)量。器件的表面粗糙度較低,藍紫光LED的表面RMS值為1.45 nm,藍綠光LED的表面RMS值為1.75 nm。在200 mA的注入電流下,藍紫光LED發(fā)光波長為411 nm,藍綠光LED的發(fā)光波長為483 nm。4.在N極性GaN模板上生長了N極性InN薄膜,研究了生長溫度、NH3流量、TMIn流量以及脈沖生長方法對N極性InN薄膜性質(zhì)的影響。結(jié)果表明,與In極性InN薄膜相比,N極性InN表面較為平坦,而In極性InN表面被六方小丘覆蓋。此外,N極性InN薄膜中存在著不同密度的In極性疇,我們認為In極性疇起源于下方GaN模板層的單晶疇邊緣,在InN生長的初始階段便形成了In極性晶核,隨著生長的進行In極性晶核逐漸長大形成單晶疇。In極性疇密度隨著生長溫度或TMIn流量的增加而增加,且隨NH3流量的減小而減少。這是由于GaN單晶疇邊緣對表面吸附的In原子的遷移具有阻擋作用,不同生長條件下In表面吸附原子的遷移能力不同,因而遷移至GaN單晶疇邊緣的幾率不同,進而形成In極性InN晶核的密度不同。N極性InN在KOH溶液中的腐蝕速率高于In極性InN的腐蝕速率。XRD測試結(jié)果顯示,相同生長條件下,N極性InN衍射峰位于31.3。,而In極性疇的衍射峰位于32.1。附近。此外,XRD極圖測試中發(fā)現(xiàn)N極性InN薄膜中存在閃鋅礦結(jié)構的InN,而且在閃鋅礦InN的側(cè)壁上還長有纖鋅礦結(jié)構的InN這種復雜結(jié)構。隨后在腐蝕后的SEM照片中我們發(fā)現(xiàn)了這種復雜結(jié)構,并且這種復雜結(jié)構具有1個上表面為N極性的閃鋅礦InN內(nèi)核和3個在側(cè)壁上生長的In極性纖鋅礦InN單晶疇。我們采用了脈沖生長法得到了晶體質(zhì)量最好的N極性InN,其(0002)面搖擺曲線半峰寬為1.35。。
[Abstract]:III nitride has excellent optical and electrical properties and is now widely used in light-emitting diodes (LEDs), lasers, photodetectors and high-power electronic devices. Generally, metal polar III nitride films have high crystal quality, while high quality N polar III nitride films are difficult to prepare, so most of them are difficult to be prepared. Metal polarity III nitride materials have been used in the devices. However, the potential of N polar III nitride has not been fully exploited. In the applications of enhanced transistors, high scaling transistors, photon detectors, solar cells, Zener tunnel diodes, and other devices, the N polarity structure will be more advantageous than the metal polar structure, N pole. The sexual structure also helps to improve the performance of LEDs and LDs, such as increasing the carrier injection efficiency, reducing the overflow of the carrier and increasing the group of In, which attracts many researchers' interest. The growth and properties of N polar GaN, InGaN and InN films on sapphire substrate are studied in this paper. The main achievements are as follows: 1. The effects of substrate dip angle, nucleation layer thickness, high temperature GaN growth temperature and Will ratio on the properties of N polar GaN film show that when the inclination angle of the sapphire substrate increases from 0.3 to 0.8., the crystal quality, optical quality and surface morphology of N polar GaN are greatly improved, mainly due to the large inclined sapphire substrate. The step density of the surface is increased and the distance between the steps is reduced, which increases the probability that the Ga adsorbed atoms contact the step and the torsional position, which is beneficial to the formation of the step flow growth mode and thus improve the crystal quality of the film. When the thickness of the nucleation layer is 20 nm, the snail dislocation and the edge dislocation density of the thin film of GaN have a minimum value, that is, The crystal quality of the thin film is the best. While the growth temperature of the high temperature GaN is increased from 1000 to 1080, the "yellow band" luminescence of the GaN film is significantly reduced. It shows that the higher growth temperature is beneficial to the improvement of the optical quality of the N polar GaN film. At the temperature of 1080, the crystal quality of the N polar GaN film is the best when the Will ratio is 1500, and its screw dislocation and edge is the blade. The dislocation density is 4.70 x 107cm-2 and 3.13 x 108cm-2 respectively. The surface RMS roughness (RMS) value is 0.331nm, and the background electron concentration and mobility reach 2.35 * 1017/cm3 and 509 cm2/V s respectively. These performance indexes are equal to Ga polarity GaN thin films, and.2. on N polar GaN template has grown on the polar polarity GaN template and studied the growth temperature. Degree, V / III ratio, the effect of TMIn flow and growth pressure on the properties of N polar InGaN films. The results show that the lower growth temperature and the large TMIn flow are the most effective methods to increase the In component of the thin film, but the increase of the In component increases the lattice mismatch between InGaN and GaN, and inevitably reduces the crystal of the InGaN thin film. The high growth temperature can improve the crystal quality and optical quality of the N polar InGaN film. At the growth temperature of 760 C and above, the thin film has a strong near band edge luminescence. While the growth temperature is lower than 740, the near band edge luminescence is weakened and the deep level luminescence gradually dominates. The equilibrium partial pressure of In is much higher than that of Ga. The proportion of In used in the gas phase to maintain the balance of the total input of In is larger, so the In component in the film is more sensitive to the input of TMIn. The surface roughness of the.N polarity InGaN film decreases with the increase of growth temperature and pressure. The higher growth pressure is beneficial to the inhibition of the decomposition of the In-N bond, while improving the crystal quality of the thin film. The N polarity LED. of blue violet light and blue and green light in the In component.3. in the film is also increased. The high satellite peak can be clearly displayed in the sample's X ray diffraction (XRD) 2 [theta] Omega scanning spectrum. It shows that the N polarity LED material has better crystal quality. The surface roughness of the device is lower, the RMS value of the blue violet LED is 1.45 nm, and the blue and green light LED. With the surface RMS value of 1.75 nm. at the injection current of 200 mA, the luminescence wavelength of blue violet LED is 411 nm, the luminescence wavelength of blue and green LED is 483 nm.4., and N polarity InN film is grown on N polar GaN template. The effect of growth temperature, NH3 flow, flow rate and pulse growth method on the properties of polar membrane are studied. Compared with the N film, the surface of the N polar InN is relatively flat, while the In polar InN surface is covered by six square hills. In addition, there are different densities of In polarity domains in the N polar InN film. We think the In polarity domain originates from the single crystal domain edge of the lower GaN template layer below, and the In polar crystal nucleus is formed at the initial stage of InN growth. The crystal nucleus gradually grows up to form a single crystal domain.In polarity domain density increases with the increase of growth temperature or TMIn flow, and decreases with the decrease of NH3 flow. This is due to the barrier effect of the migration of In atoms adsorbed on the surface of GaN single crystal, and the migration ability of the adsorbed atoms on the surface of In is different under different growth conditions and thus migrates to Ga. The probability of the domain edge of the N single crystal is different, and then the density of the In polarity InN nucleus is formed. The corrosion rate of the.N polar InN in KOH solution is higher than that of the In polar InN, and the results show that the InN diffraction peak of N polarity is located in the 31.3., and the diffraction peak of the polarity domain is located near the same growth condition. The present N polar InN film has a InN of sphalerite structure and the complex structure of the zinite structure on the side wall of the sphalerite InN. This complex structure has been found in the SEM photos after corrosion, and this complex structure has 1 sphalerite InN kernel on the surface of N polarity and 3 growth on the side wall. The In polar wurtzite InN single crystal domain is obtained. The N polar InN with the best crystal quality is obtained by pulse growth method, and its (0002) rocking curve half peak width is 1.35..
【學位授予單位】：吉林大學
【學位級別】：博士
【學位授予年份】：2016
【分類號】：TN312.8

【參考文獻】

相關期刊論文 前1條

1 陸大成,段樹坤;A Quasi-Therm odynam ic Model of MOVPE of InGaN[J];半導體學報;2000年02期

，

本文編號：1974249