热处理升温快慢对非晶硅中形成的纳米硅粒尺寸的影响

含氢非晶硅薄膜经过快速热退火处理后,我们用拉曼散射和X-射线衍射技术对样品进行分析.我们的实验结果表明:在非晶硅薄膜中形成的纳米硅晶粒的大小随着热退火过程中升温快慢而变化.在升温过程中,当单位时间内温度变化量较大时（～100℃/s）,则所形成纳米硅粒较小（～1.6～15nm）;若单位时间内温度变化量较低（～1℃/s）,则纳米硅粒较大（～23～46nm）。根据分形生长理论和计算机模拟,我们讨论了升温快慢与所形成的纳米硅颗粒大小的关系.     

利用热退火法从非晶硅薄膜中生长纳米硅粒

报道了一种从氢化非晶硅薄膜中生长纳米硅粒的方法.氢化非晶硅薄膜经过不同条件的热退火处理后,用拉曼散射和X射线衍射技术对样品进行了分析.实验结果表明:在快速升温条件下所形成的nc-Si在薄膜中的分布是随机均匀的,直径在1.6～15 nm范围内,硅粒大小随退火过程中升温快慢而变化.     

a-Si:H热处理过程中形成的纳米硅粒及其光致发光

报道了氢化非晶硅薄膜在600～620℃温度下快速退火10 s可以形成纳米晶硅,其拉曼散射表明,所形成的纳米晶硅在薄膜中的分布是随机的,其直径在1.6～15 nm内.根据晶体生长理论和计算机模拟,讨论了升温快慢与所形成纳米硅颗粒大小之间的关系,并且在强光照射下观察了纳米晶硅在薄膜中的结晶和生长情况.经退火形成的nc-Si可见光辐射较弱,不能检测到它们的光致发光,但用氢氟酸腐蚀钝化后则可检测到较强的红PL,并且钝化后的nc-Si在空气中暴露一定时间后,其辐射光波长产生了蓝移.就表面钝化和量子限制对可见光辐射的重要性作了讨论.     

通用工艺与设备 热处理与表面处理工艺

0626019阳极氧化中烧损行为及防止〔刊,中〕/王平//西华大学学报(自然科学版).—2006,25(4).—41-43(G)0626020利用热退火法从非晶硅薄膜中生长纳米硅粒〔刊,中〕/薛清//量子电子学报.—2006,23(4).—565-568(L)报道了一种从氢化非晶硅薄膜中生长纳米硅粒的方法。氢化非晶硅薄膜经过不同条件的热退火处理后,用拉曼散射和X射线衍射技术对样品进行了分析。实验结果表明:在快速升温条件下所形成的nc-Si在薄膜中的分布是随机均匀的,直径在1.6~15nm范围内,硅粒大小随退火过程中升温快慢而变化。参70626021脉冲电沉积Ni-W合金镀层的摩擦磨损性…     

氢化非晶硅薄膜退火形成的纳米硅粒

报道了氢化非晶硅薄膜在600～620℃温度下快速退火10s可以形成纳米晶硅,其喇曼散射表明,在所形成的纳米晶硅在薄膜中分布是随机的,其直径在1.6～15nm以内.并且在强光照射下观察了纳米晶硅在薄膜中的结晶和生长情况.     

快速热退火制备多晶硅薄膜的研究

采用等离子体增强化学气相沉积法(PECVD)沉积非晶硅薄膜,然后在快速热退火炉中进行退火。研究了升温速率、降温速率对晶化的影响。结果表明:退火中,升温速率越大,越不利于晶核的形成;降温速率较小时(100℃/60s),形成的晶粒尺寸较小,晶化情况较好,晶化率估算达64.56%。     

利用快速退火法控制非晶硅薄膜中纳米硅粒尺寸

报道了利用快速退火法控制膜中纳米硅粒大小的方法,讨论了升温快慢与所形成的纳米硅粒大小的关系.     

a-SiOx:H/a-SiOy:H多层薄膜微结构的退火行为

采用PECVD技术在P型硅衬底上制备了a-SiOx:H/a-SiOy:H多层薄膜,利用AES和TEM技术研究了这种薄膜微结构的退火行为.结果表明:a-SiOx:H/a-SiOy:H多层薄膜经退火处理形成nc-Si/SiO2多层量子点复合膜,膜层具有清晰完整的结构界面.纳米硅嵌埋颗粒呈多晶结构,颗粒大小随退火温度升高而增大.在一定的实验条件下,样品在650℃下退火可形成尺寸大小合适的纳米硅颗粒.初步分析了这种多层复合膜形成的机理.     

a-SiO_x∶H/a-SiO_y∶H多层薄膜微结构的退火行为

采用 PECVD技术在 P型硅衬底上制备了 a- Si Ox∶ H/a- Si Oy∶ H多层薄膜 ,利用 AES和 TEM技术研究了这种薄膜微结构的退火行为 .结果表明 :a- Si Ox∶ H/a- Si Oy∶ H多层薄膜经退火处理形成 nc- Si/Si O2 多层量子点复合膜 ,膜层具有清晰完整的结构界面 .纳米硅嵌埋颗粒呈多晶结构 ,颗粒大小随退火温度升高而增大 .在一定的实验条件下 ,样品在 650℃下退火可形成尺寸大小合适的纳米硅颗粒 .初步分析了这种多层复合膜形成的机理     

SiC/SiO_2镶嵌结构薄膜光致发光特性研究

采用 SiC/SiO_2复合靶,用射频磁控共溅射技术和高温退火的方法制备了 SiC/SiO_2纳米镶嵌结构复合薄膜,并应用傅里叶红外吸收(FTIR),X 射线衍射(XRD),扫描电镜(SEM)和光致发光(PL)实验分析了薄膜的结构、表面形貌以及光致发光性能。结果表明,样品经高温退火后在 SiO_2基质中有 SiC 纳米颗粒形成。以 280 nm 波长光激发样品薄膜表面,显示出较强的 365 nm 的紫外光发射以及 458 nm 和 490 nm 处的蓝光发射,其发光强度随退火温度从 800℃升高至 1 050℃而增强。其发光归结为薄膜中与 Si-O 相关的缺陷形成的发光中心。     

Size Control of Nanoscale Silicon Particles Formed in Thermally Annealed A-Si∶H Films and Its Photoluminescence

A method to control the si ze of nanoscale silicon grown in thermally annealed hydrogenated amorphous silico n (a-Si∶H) films is reported. Using the characterizing techniques of micro-Ra man scattering, X-ray diffraction and computer simulation, it is found that the sizes of the formed silicon particles change with the temperature rising rate i n thermally annealing the a-Si∶H films. When the a-Si∶H films have been anne aled with high rising rate( ~100 ℃/s), the sizes of nanoscale silicon particle s are in the range of 1.6~15 nm. On the other hand, if the a-Si∶H films have been annealed with low temperature rising rate(~1 ℃/s), the sizes of nanoscale silicon particles are in the range of 23~46 nm. Based on the theory of crystal nucleation and growth, the effect of temperature rising rate on the sizes of th e formed silicon particles is discussed. Under high power laser irradiation, in situ nanocrystallization and subsequent nc-Si clusters are small enough for vis ible light emission, authors have not detected any visible photoluminescence(PL) from these nc-Si clusters before surface passivation. After electrochemical ox idization in hydrofluoric acid, however, intense red PL has been detected. Cycli c hydrofluoric oxidization and air exposure can cause subsequent blue shift in t he red emission. The importance of surface passivation and quantum confinement i n the visible emissions has been discussed.     

Size Control of Nanoscale Silicon Particles Formed in Thermally Annealed A- Si: H Films and Its Photoluminescence

A method to control the size of nanoscale silicon grown in thermally annealed hydrogenated amorphous silicon (a-Si : H) films is reported. Using the characterizing techniques of micro-Raman scattering,X-ray diffraction and computer simulation, it is found that the sizes of the formed silicon particles change with the temperature rising rate in thermally annealing the a-Si : H films. When the a-Si: H films have been annealed with high rising rate( ～ 100 C/s), the sizes of nanoscale silicon particles are in the range of 1.6～ 15nm. On the other hand, if the a-Si: H films have been annealed with low temperature rising rate(～1 C/s),the sizes of nanoscale silicon particles are in the range of 23～46 nm. Based on the theory of crystal nucleation and growth, the effect of temperature rising rate on the sizes of the formed silicon particles is discussed. Under high power laser irradiation, in situ nanocrystallization and subsequent nc-Si clusters are small enough for visible light emission, authors have not detected any visible photoluminescence(PL) from these nc-Si clusters before surface passivation. After electrochemical oxidization in hydrofluoric acid, however, intense red PL has been detected. Cyclic hydrofluoric oxidization and air exposure can cause subsequent blue shift in the red emission. The importance of surface passivation and quantum confinement in the visible emissions has been discussed.     

低温高速率沉积非晶硅薄膜及太阳电池

采用射频等离子体增强化学气相沉积(RF-PECVD)技术,保持沉积温度在125℃制备非晶硅薄膜材料及太阳电池。在85 Pa的低压下以及400～667 Pa的高压下,改变Si H4浓度和辉光功率等沉积参数,对本征a-Si材料的性能进行优化。结果表明,在高压下,合适的Si H4浓度和压力功率比可以使a-Si材料的光电特性得到优化,并且薄膜的沉积速率得到一定程度的提高。采用低压低速和高压高速的沉积条件,在125℃的低温条件下制备出效率为6.7%的单结a-Si电池,高压下本征层a-Si材料的沉积速率由0.06～0.08 nm/s提高到0.17～0.19 nm/s。     

非晶硅薄膜YAG激光微晶化晶粒生长研究

以单晶硅(111)为衬底,以等离子体增强化学气相沉积技术制备的非晶硅薄膜为前驱物,采用YAG激光晶化技术实现从非晶硅薄膜到纳米晶硅薄膜的相变过程。采用X射线衍射仪和原子力显微镜对YAG激光晶化薄膜进行了表征与分析。结果表明:薄膜的晶粒尺寸在纳米级;随着激光脉冲频率的增加,晶粒尺寸先变大后变小,其最佳结晶频率区间为10～12 Hz。     

Deposition and crystallization of a-Si thin films by rapid thermal processing

The deposition and crystallization of a-Si thin films grown by rapid thermal processing have been studied, using transmission electron microscopy. The a-Si films were deposited in a rapid thermal processor at reduced pressures in the temperature range of 530–580°C, at different deposition pressures and silane flow rates and subsequently were annealed in-situ by high temperature rapid thermal annealing (RTA) or by a two-step annealing process involving low temperature furnace annealing (FA) followed by high temperature RTA. The activation energy of a-Si deposition was found to be approximately 1.7 eV, in reasonable agreement with the conventional LPCVD technique. It has been found that the deposition temperature and deposition rate have a strong effect on the grain size, which is attributed to the nucleation processes in the bulk of the films. The combination of low deposition temperature, high deposition rate and a two-step annealing process permits the low temperature growth of poly-Si films of 100 nm thickness, with large grains of 520 nm size, containing a low density of microtwins and characterized by very low surface roughness of 2.2 nm.     

隔热结构中非晶硅的释H_2机理与工艺研究

对采用等离子增强化学气相淀积法(PECVD)制备的氢化非晶硅(a-Si:H)薄膜进行了退火释H2实验,并对三文治结构膜层生长工艺作了改进。红外透射光谱表明:提高退火温度及增加退火时间会造成Si-H键断裂释放H2影响器件结构完整;不断改进设计,最终采用精简有效热敏面积及将退火工艺提前以扩张释H2渠道的方案,获得600℃退火后仍保持完整三文治结构的优化设计流程。