激光辐照固态Al膜制备p型重掺杂4H-SiC

通过激光辐照固态Al膜,制备了一种p型重掺杂4H-SiC,分析了Al膜厚度、激光脉冲个数对掺杂结果的影响,验证了不同工艺参数对p型掺杂层表面电学性能的调控作用。结果表明,当Al膜厚度为120nm,脉冲个数为50时,掺杂试样的最大载流子浓度为6.613×10~(17) cm~(-3),最小体电阻率为17.36Ω·cm,掺杂浓度(粒子数浓度)可达6.6×10~(19) cm~(-3)。4H-SiC的Al掺杂改性机理为:在紫外激光作用下,Si—C键断裂,Al原子替代Si原子形成p型掺杂层。     

电子束掺杂磷

本文提出了一种新的半导体掺杂方法.将掺杂杂质涂敷在待掺杂的半导体表面,利用连续电子束辐照实现了掺杂.其结深可由电子束的参数调节加以控制. 对掺磷的电子束掺杂层进行测量分析,表明,N_P=3.5 × 10~(10)cm~(-3),层内N(x)的变化范围为 10~(12)-10~(20)cm~(-3),μ(x)为 57-130(cm~2/V·scc);低能电子衍射图案呈单晶衍射点和菊池线;沟道背散射测量电子束掺杂层损伤比离子注入的小得多.用这一掺杂法研制成功的平面二极管,性能良好.     

高效率Ku波段HBTMMIC功率放大器

<正> 这种MMICPA所用的器件结构是用MOCVD系统生长的,依次为1.5μm厚的重掺杂n-GaAs下集电极、0.7μm厚的掺杂为2×10~(16)cm~(-3)的集电极、5×10~(19)cm~(-3)碳掺杂基极(厚度80nm)、100nm厚的掺杂浓度为5×10~(17)cm~(-3)的Al_(0.35)Ga_(0.65)As发射极和200nm厚的掺杂     

10keV B~+注入预非晶化Si的剩余缺陷和浅结

<正> 一、问题的提出和实验方法 在低能注入B~+浅结的过程中,沟道效应难以避免。为避免B~+注入的沟道效应,本文采用100keV下5×10~(15)cm~(-2)的Si~(29)注入n-Si<100>进行非晶化处理。继而进行了10keV,1×10~(15)cm~(-2)的B~+注入形成浅结,然后对样品进行快速热退火(RTA)处理,并观察界面缺陷的     

工业纯铁离子注Ti层激光加热前后的组织结构

本文用X-ray、TEM技术研究了60KV、5×10~(17)Ti~+/cm~2注入工业纯铁表面后经CW CO_2激光加热前后的组织结构,同时,用AES对注入层的成分进行了分析。     

加热的GaAs中锰和铁的热再分布

应用光学、电学、质谱和谐振技术,发现非掺杂的体GaAs样品中锰和铁的本底浓度为(?)10~(15)cm~(-3),当加热时进行再分布,于近表面区形成一个浓度约为10~(17)cm~(-3)的薄(1～3μm)层,并指出锰的再分布能引起表面导电类型的改变。     

重掺杂硅的热氧化

研究干氧和湿氧(95℃H_2O)氧化膜厚度在0.10～1.0μ,温度在920℃～1200℃的范围内重掺杂硅氧化特性,研究硅掺硼(1×10~(16)～2.5×10~(20)cm~(-3))或掺磷(4×10~(15)～1.5×10~(20)cm(-3)),以及这两种元素在硅表面的淀积。当硼浓度大于1×10~(20)/cm~3的情况,所有温度下氧化速率增加,而干氧氧化时这种影响最明显。1000℃以上,P掺硅氧化速率增加没有这样快,而920下,P的浓度1×10~(19)cm~(-3)或更高,结果使氧化速率有明显的增加,磷掺杂的影响在湿氧中最明显,这个结果可以用改硅热氧化时杂质再分布来园满地介释。这些考虑还能得到其他杂质重掺杂影响氧化速率的试验值。 高温度下，硅在各种氧化气氛中反应生成SiO_2,单晶硅热氧化的动力学是最近几篇论文的题目（1-5）。这些论文作者报导了起过所研究的浓度范围时氧化速率不依赖于体掺杂浓度。受主杂质和花主杂质的浓度从很低的值（本证硅）到大概象1×10~(20)cm~(-3)那样高，然而还要注意，氧化杂质浓度大于10~（20）cm~(-3)的硅表面时，氧化速率经常偏离标准值为6或7。对于大部分偏差用做器件的扩散工艺的样品来发现的。近来，发展表面控制器件和集成电路中哇氧化的作用日益重要，同时精密控制氧化层的厚度变得更有兴趣（8，9）。因此，着于研究决定对掺杂     

用激光诱发淀积的Hg_(0.7)Cd_(0.3)Te外延生长

在130℃用激光诱发淀积法(LAD)在(111)A面CdTe衬底上生长了n型Hg_(0.7)Cd_(0.3)Te。在77K,其电子迁移率为4000～7000cm~2/V·s,载流子浓度为(0.7～3)×10~(16)cm~(-3)。外延薄膜经过410℃退火后可以转变成p型。已用离子注入制成了n~+/p光电二极管。     

优质GaAs/Si材料的研制

用国产分子束外延设备(Ⅳ型)在p型Si衬底上用三阶段生长法生长出优质GaAs外延层。测试样品为2μm厚,n型掺杂浓度5×10~(16)cm~(-3)。测量结果为x射线双晶衍射回摆曲线半峰宽225弧秒;低温光荧光谱半峰宽在10K时为5meV,外延层表面位错密度10~6cm~(-2)。     

用脉冲激光把稀土元素Yb引入硅单晶中

用Q开关Nd:YAG脉冲激光辐照淀积在Si上的稀土元素Yb,当输出能量密度≥6.0J/cm~2时,成功地把Yb引入Si中.用二次离子质谱(SIMS)分析指出进入Si中Yb的表面浓度为3 ×10~(11)/cm~3,在离表面 0.75μm处,浓度仍有 7 ×10~(19)/cm~3.     

Control of Al and B doping transients in 6H and 4H SiC grown by vapor phase epitaxy

The atomic concentration profiles in 4H and 6H SiC created by Al and B doping turn-on and turn-off during vapor phase epitaxy (VPE) was investigated by secondary ion mass spectrometry (SIMS). It was found that dopant traces were adsorbed to the reactor walls and re-evaporated after the dopant precursor flow was switched off. This adsorption/re-evaporation process limits the doping dynamic range to about three orders of magnitude for Al, and two orders of magnitude for B. An order of magnitude in doping dynamics could be gained by simultaneously switching the gases and changing the C:Si precursor ratio. By adding a 10 min growth interruption with an H or HC1 etch at the doping turn-off, the background doping tail could be considerably suppressed. In total, a doping dynamics for Al of almost five orders of magnitude can be controlled within a 30 nm layer. For B, the dynamic range is more than three orders of magnitude, and the abruptness is most probably diffusion limited. Abackground doping level of 2 × 10¹⁵ cm⁻³ for Al and 2 × 10¹⁶ cm⁻³ for B was obtained. For Al, the background doping is most probably due to the adsorption/re-evaporation of dopants at the reactor walls; while for B, the background doping may in addition be limited by diffusion.     

HV/CVD系统Si、SiGe低温掺杂外延

研究了硼烷（B2H6）掺杂锗硅外延和磷烷（PH3）掺杂硅外延的外延速率和掺杂浓度与掺杂气体流量的关系．B浓度与B2H6流量基本上成正比例关系;生长了B浓度直至1019cm-3的多层阶梯结构,各层掺杂浓度均匀,过渡区约20nm,在整个外延层,Ge组分（x=0.20）均匀而稳定．PH3掺杂外延速率随PH3流量增加而逐渐下降;P浓度在PH3流量约为1.7sccm时达到了峰值（约6×1018cm-3）．分别按PH3流量递增和递减的顺序生长了多层结构用以研究PH3掺杂Si外延的特殊性质．     

石墨掺杂对B/KNO_3点火药的激光点火特性的影响

用光声检测的实验方法研究石墨掺杂对B／KNO3点火药的激光点火性能的影响。根据对光声谱的分析，指出了石墨掺入B／KNO3会略降低B／KNO3的激光吸收能力并且掺入量增加时，药剂的光吸收能力会有所改善。石墨掺杂会增长B／KNO3的激光点火延迟期，这一规律与石墨掺杂对B／KNO3的吸光性能的影响规律一致。     

梯度掺杂生长绒面结构ZnO:B-TCO薄膜及其特性研究

采用新的金属有机化学气相淀积(MOCVD)-ZnO镀膜工艺技术-梯度掺杂技术生长绒面结构。研究ZnO:B-TCO薄膜。结果表明,梯度掺杂技术可有效增加薄膜晶粒尺寸和提高光散射作用。并且,梯度掺杂技术有效地提高了薄膜在近红外区域的光学透过率,有利于应用于宽谱域薄膜太阳电池。生长获得的MOCVD-ZnO薄膜,其薄膜电子迁移率为24 cm2/V,电阻率为2.17×10-3Ω.cm,载流子浓度为1.20×1020cm-3,且在小于1 000 nm波长范围内的平均透过率大于85%。     

Er3+/Yb3+共掺Bi2O3-GeO2-Na2O玻璃的上转换发光

研究了不同Er3 /Yb3 掺杂比46Bi2O3-44GeO2-10Na2O(B46G44N10)(摩尔分数)玻璃的吸收光谱、红外吸收谱和上转换光谱性质,分析了玻璃中Yb3 敏化Er3 的上转换发光机制。测试了Er3 离子在不同Yb3 浓度下玻璃中的上转换荧光强度,得到最佳的掺杂质量比Er3 ∶Yb3 =1∶6。计算了在980 nm激发下Er2O3质量分数为0.5%和Yb2O3质量分数为3.0%的Er3 /Yb3 共掺B46G44N10玻璃的绿光上转换效率为2.27×10-4。比较了不同基质材料玻璃的上转换效率,结果表明B46G44N10玻璃是一种良好的上转换基质材料。     

Upconversion fluorescence modulation of CaTiO3:Yb3+/ Er3+ nanocubes via Zn2+ introduction

rials, CaTiO3:Yb3+/Er3+/Zn2+ nanocubes with uniform size were prepared by solvothermal method in this paper. They were respectively characterized by X-ray diffractometer (XRD), scanning electron microscope (SEM), photoluminescence (PL) spectroscopy and their fluorescence lifetimes. The results show that the average size of the nanocubes is about 550 nm×650 nm×850 nm with good upconversion luminescence (UCL) properties. Under 980 nm laser excitation, the effects of the ratio between activator Er3+ and sensitizer Yb3+ and Zn2+ doping on the upconversion fluorescence properties were investigated, and the optimal ion ratio was obtained. The results of steady-state spectra show that the strongest fluorescence intensity of CaTiO3:Yb3+/Er3+ was obtained with the addition of 10 mol% Zn2+ at a Yb3+/Er3+ molar doping ratio of 3:0.3, which was attributed to the crystal field asymmetry generated by the introduction of Zn2+ ions. The energy transfer and upconversion mechanism between Yb3+ and Er3+ ions in CaTiO3 nanocubes were investigated by analyzing the upconversion fluorescence kinetics.     

中间层掺杂对具有隧穿结构的非晶硅/微晶硅叠层电池的影响

为了提高非晶硅/微晶硅叠层电池的转换效率和稳定性,在隧穿结构中引入ZnO∶B中间层,研究了中间层掺杂情况对叠层电池短路电流密度、开路电压、填充因子、转换效率等性能的影响。实验结果表明:最佳的非晶硅/微晶硅叠层电池中间层为厚度较薄、掺杂浓度较高的ZnO∶B,有利于叠层电池整体性能的提高。最终,采用厚度为40 nm,B2H6流量为5 ml/min的ZnO∶B中间层,制备出了初始效率为12.2%、衰退率在8%以内的叠层电池。     

Self-Aligned Transistors with Polysilicon Emitters for Bipolar VLSI

A new bipolar process technology for fabricating self-aligned transistors with polysilicon contacted emitters is described. The extrinsic base regions of the transistor are self-aligned to the emitter contact by exploiting the effects of concentration-dependent oxidation to selectively oxidize the polysilicon. The shallow emitter is fabricated with a thin oxide layer at the polysilicon-silicon interface, thereby enhancing the emitter efficiency and thus the current gain of the device. It is demonstrated that this gain enhancement can be traded for a considerable increase in active base doping, with a resulting decrease in base resistance and potential improvement in switching performance. Under certain circumstances, non-ideal electrical characteristics can be obtained from the self-aligned transistor which are caused by lateral spread of the extrinsic base region beneath the sidewall oxide of the polysilicon emitter contact. Tlris leads to the formation of p/sup +/ -n/sup +/ junction at the periphery of the emitter and hence to tunneling of carriers across this region. It is shown that the same tunneling mechanism also limits the extent to which the active base doping can be increased. In order to avoid the formation of the peripheral p/sup +/-n/sup +/ junction, a polysilicon base contact is employed which allows a self-aligned extrinsic base region to be fabricated with negligible lateral movement.     

Li_2MgSiO_4微波介质陶瓷的低温烧结适应性

采用固相法制备了添加B2O3的Li2MgSiO4陶瓷,研究了添加B2O3助剂对降低Li2MgSiO4陶瓷烧结温度的作用,以及B2O3对所制陶瓷的密度、相结构与微观形貌、微波介电性能的影响。结果表明,添加质量分数2%的B2O3就可在810℃的低温下实现Li2MgSiO4陶瓷的致密烧结,并获得较佳的介电性能:εr=5.84,Q.f=107 000 GHz(f=8 GHz),可用于制作LTCC材料。     

离子注入降低PtSi肖特基二极管的势垒高度

Pt Si肖特基二极管的势垒高度制约 Pt Si红外探测器的截止波长和量子效率 .在 Pt Si/Si界面注入 In+ 、B+ ,采用高浓度、浅层注入避免隧穿效应 ,用 Ar气保护热处理消除注入损伤 ,附加掩膜层控制离子注入深度 ,成功地将 Pt Si肖特基二极管的势垒高度降低到 0 .1 5e V.