硅中注铅的连续CO_2激光退火行为

在(111)Si中以 350 keV,1×10~(15)和 5×10~(15)/cm~2注入Pb并进行连续 CO_2激光退火.用背散射RBS和透射电子显微镜TEM研究退火前后的杂质分布和辐射损伤.实验表明,上述退火处理能消除以剂量1×10~(15)/cm~2注入形成的损伤,而当剂量为5×10~(15)/cm~2时,在超过溶解度的高杂质浓度区,外延生长受到阻挡.再生长终止以后,表面形成多晶结构,杂质沿晶粒边界向外扩散.     

高浓度注砷和注锑硅的连续氩离子激光退火研究

对高浓度注砷硅(双能量注入150 keV、1.05 × 10~(14)cm~(-2)和 60 keV、3.5×10~(15)cm~(-2)的连续Ar~+激光退火进行了研究.实验发现只有在合适的样品预热温度和激光功率的条件下才能获得最高的电激活率.过高的预热温度,因亚稳态载流子浓度弛豫现象而使电激活率降低;但过低的预热温度,因需要更大的激光功率而使硅表面产生严重损伤,甚至产生微细裂纹.这种现象在高浓度注锑硅(150keV、10~(16)cm~(-2))样品中同样存在.     

硅中注铋脉冲激光退火的研究

本文报导了采用165 keV He~+离子沟道背散射技术研究高剂量铋注入<111>硅后,进行脉冲激光退火的效果,并和热退火作了比较。热退火温度达到900℃时,剩余晶格损伤还有35％;在750℃下退火时,铋的替位率达到最大值50％,温度再升高,替位率反而下降;在退火温度高于625℃时就产生大量铋原子的外扩散。面脉冲激光退火后,晶格损伤几乎全部消除,铋原子进行再分布,它在硅中的浓度可超过固溶度一个数量级,且95％以上处于替代位置。文中还就不同激光能量下的退火情况作了比较。     

离子注入硅的连续CO2激光退火

激光退火用在半导体材料上，现在国内外都还在试验阶段，所用的激光器主要是红宝石激光器、钕玻璃激光器和氩离子激光器。     

连续波CO_2激光退火消除硅中氧化层错的研究

用150瓦连续波CO_2激光束照射硅片,观察到了其氧化层错的消除现象,并对消除机理进行了探讨。     

离子注入CO_2激光退火硅中的深能级缺陷

在注As硅中观察到7个深能级谱峰.CO_2激光退火是消除离子注入引入的深能级缺陷的有效方法.消除深能级缺陷的功率密度范围为 350W/cm~2-600W/cm~2与注入杂质激活的功率密度范围基本一致.功率密度高于600W/cm~2的CO_2激光扫描,在样品中引入比较单纯比较清洁的滑移位错.用DLTS测量,测得滑移位错的深能级为H(0.33eV).     

离子注入硅Nd-YAG连续激光退火

本文报导用扫描Nd-YAG连续激光对<100>硅中注铋的损伤层进行的退火研究。测量表明:退火能使离子注入造成的晶格损伤很好恢复,90％以上的铋原子处于替代位置,杂质浓度的分布保持不变。文中对退火参数的选择、均匀性,以及表面温度升高、外延再生长层厚度等问题进行了讨论。文末还将实验结果与熔化型脉冲激光退火进行了比较。     

硅晶圆中注入10 MeV磷的连续激光退火激活

基于硅(Si)中高能注入磷(P)的连续激光退火方法展开研究。采用的P离子最高注入能量为10 MeV,在Si中的注入深度可达7μm。分别采用532nm和808nm波长的连续激光退火,照射时间分别为2ms和27ms。结果显示,虽然532nm激光在Si中的穿透深度只有125μm,不到808nm激光的1/10,但由于照射时间较长,热传导起到主要作用。因此,两种退火方案都可以实现整个注入深度的有效激活。532nm连续激光退火实现了93的激活效率,808nm激光退火的激活效率接近100。     

CW CO_2激光退火后离子注入硅片的性质研究

当激光功率、束斑直径和硅片预热温度一定时,存在一临界扫描速度。当激光扫描速度小于此临界位时,CW CO_2激光退火具有和热退火相同的载流子浓度、方块电阻、折射率、消光系数和反射率,但激光退火后少子扩散长度要比热退火的大几倍。     

磷砷化镓离子注入层的CW CO_2激光退火研究

本文对N、Zn离子注入GaAs_(1-x)Px材料之后,用连续CO_2激光束进行退火作了研究.晶格恢复、注入杂质的激活率和光致发光的实验测量结果表明,CO_2激光退火的效果优于常规热退火.本文对CO_2激光退火效果优于热退火的原因作了初步的解释.     

CW laser annealing of boron implanted polycrystalline silicon

The electrical characteristics have been measured on CW laser annealed boron implanted polycrystalline silicon layers. It is shown, that a resistivity can be obtained, which is only about double that of a single crystalline layer doped to the same level. By appropriate choice of doping and laser annealing parameters, a temperature coefficient close to zero can be achieved. It is also shown that laser irradiation can be used to trim a furnace annealed polysilicon resistor to a desired resistance value.     

高气压连续CO2激光器的输出功率

<正>随气体压力增加,单位时间流过激光器的激活介质增加,可望获得较大的输出功率,并能改善器件的封闭寿命和输出稳定性.待研究的装置见图1.在些装置中,以金属板ABCD为阳极,EFGK为阴极(可以是管、板或针状),极问距离AE=H.假定电子密度n在正柱区     

A CW CO2 laser with DC-discharge preionization

The application of the plasma-injection technique (involving DC-discharge preionization) to a CW CO₂ laser operating with recirculated gas is described. Measured characteristics of the discharges, the gain, and the output power are presented. An output of 110 W was obtained with a specific efficiency of 1.0 J/l^-1 of flowed gas at a pressure of 10 kPa. A simplified model to calculate a characteristic length of the main discharge, which is useful for design purposes, is developed. This type of laser may be scaled simply to higher output powers, requires a gas mixture with only 20% He, is compact and robust, and yet is simple in its electrical and mechanical requirements     

无He横流连续CO2激光器的新进展

在横流CO2激光器中,我们以Ar(CO2-N2-Ar)代He(CO2-N2-He)实现了1kW连续激光输出,并获得以CO2-N2实现了1.2kW连续激光输出的稳定运行。     

Scaling of laser power with N2 partial pressure in aconvective-cooled CW CO2 laser

Diffusion-cooled and convective-cooled CW CO₂ lasers have significantly different N₂ partial pressure in their optimum laser gas mixture. While in diffusion-cooled lasers the N₂ fractional concentration is normally within 20% of the total gas pressure, it ranges up to 60% in convective-cooled lasers. By considering various effects of N₂ and solving a simplified rate-equation model analytically, the large difference in the optimum N ₂ concentrations in these two types of CO₂ laser is explained     

硅对CO_2激光的增强吸收

测量离子注入硅片对强连续CO_2激光的透射率和反射率随辐照时间的变化,发现硅有极强的能量吸收。这一现象可定性地用自由载流子吸收来解释。     

CW 20-kW SAGE CO2 laser for industrial use

A CW CO₂ laser with power output of more than 20 kW is described. The laser consists of a discharge excitation system named SAGE (Silent-discharge Assisted Glow discharge Excitation) and a ZnSe or KCl transmissive window for extracting high-quality beams with axisymmetric intensity profile from a confocal positive-branch unstable resonator. SAGE is effective in forming a uniformly distributed and stable discharge in a large-volume, high-pressure gas excitation medium. Together with appropriate high-pressure gas conditions and a properly selected zeolite to adsorb water vapor in the laser chamber, the transmissive windows enable gas-sealed operations. The structure of the 20-kW SAGE laser and its performance characteristics are described. The maximum CW power of 26.5 kW with an efficiency of 16.5% is attained with the ZnSe window, and a 20.3-kW power output is extracted through the KCl window. Long-term gas-sealed operation at a CW power level of 20 kW has been demonstrated for a period of 65 h     

高效率横向电激励连续CO_2激光器的研究

报道一种工业用高气压封闭形横向电激励二千瓦级连续CO_2激光器。连续运行13小时,输出功率高于2.3kW,能量转换效率大于17％。研究了放电特性、输出特性;测量了在不同放电条件下的电子温度和电子浓度。     

1kW无氦横流连续CO_2激光器的研究

本文报道我们研制的 Ikw无 He横流连续CO_2激光器的实验结果。激光器总体结构如图1所示。其放电装置采用针板放电结构，阴极由152根直径为      

Preionizer-induced pulsed-mode operation of a transverse-flowtransversely excited CW CO2 laser

A pulse-preionized, dc-excited, transverse-flow, CW CO₂ laser has been operated in pulsed mode without using a discharge power-switching scheme. The pulsation in laser power is produced by a pulsed current that flows from the dc power supply due to the collapse in the discharge impedance whenever a preionizer pulse appears. By properly choosing the preionizer-pulse repetition frequency, dc power-supply filter-capacitor value, and gas composition, the laser pulsation has been enhanced. This laser has been operated at 1-kW average laser power level in pulsed mode at 1.3-kHz pulse repetition frequency with a peak-to-average power ratio of 3.35 and laser-power modulation depth of almost 100%