1MeVSi~＋衬底加温注入Al＿（0．3）Ga＿（0．7）As／GaAs超晶格和GaAs的晶格损伤研究

用卢瑟福背散射／沟道技术研究了１ＭｅＶＳｉ￣＋在衬底加温和室温下以不同剂量注入Ａｌ＿（０．３）Ｇ＿（０．７）Ａｓ／ＧａＡｓ超晶格和ＧａＡｓ后的晶格损伤。在衬底加温下，观察到Ａｌ＿（０．３）Ｇａ＿（０．７）Ａｓ／ＧａＡｓ超晶格和ＧａＡｓ都存在一个动态退火速率与缺陷产生速率相平衡的剂量范围，以及两种速率失去平衡的临界剂量。超晶格比ＧａＡｓ更难以损伤，并且它的两种速率失去平衡的临界剂量也大于ＧａＡｓ中的相应临界剂量，用热尖峰与碰撞模型解释了晶格损伤积累与注入剂量和衬底温度的关系。用ＣＮＤＯ／２量子化学方法计算了ＧａＡｓ和Ａｌ＿ｘＧａ＿（１－ｘ）Ａｓ中化学键的相对强度，并根据计算结果解释了注入过程中Ａｌ＿（０．３）Ｇａ＿（０．７）Ａｓ／ＧａＡｓ超晶格和ＧａＡｓ中晶格损伤程度的差别。     

低压－金属有机物汽相外延生长的Ga＿（1－x）In＿xAs／InP激光器中深能级的研究

应用深能级瞬态谱（ＤＬＴｓ）技术详细研究低压－金属有机物汽相外延（ＬＰ－ＭＯＶＰＥ）生长的Ｇａ＿（０．４７）Ｉｎ＿（０．５３）Ａｓ／Ｉｎｐ量子阱、宽接触和质子轰击条形异质结激光器中的深能级。样品的ＤＬＴＳ表明，在宽接触激光器的ｉ－Ｇａ＿（０．４７）Ｉｎ＿（０．５３）Ａｓ有源层里观察到Ｈ１（Ｅ＿ｖ＋０．０９ｅＶ）和Ｅ１（Ｅ＿ｃ－０．３５ｅＶ）陷阱，它们可能分别与样品生长过程中扩散到ｉ－Ｇａ＿（０．４７）Ｉｎ＿（０．５３）Ａｓ有源层的Ｚｎ和材料本身的原生缺陷有关。而条形激光器的ｉ－Ｇａ＿（０．４７）Ｉｎ＿（０．５３）Ａｓ有源层的Ｈ２（Ｅ＿ｖ＋０．１１ｅＶ）和Ｅ２（Ｅ＿ｖ－０．４２ｅＶ）陷阱则可能是Ｈ１和Ｅ１与质子轰击引起的损伤相互作用的产物。     

Ga1—xAlxAs外延片有源区Al组份的测定方法

由于ＧａＡｓ与ＡｌＡｓ晶格常数相近，ＧａＡｓ晶格常数为０．５６５３５ｎｍ，ＡｌＡｓ的晶格常数为０．５６６０５ｎｍ，当固熔体中Ａｌ组份ｘ值从０变到１时，晶格常数变化约为０．１５％．因此，在ＧａＡｓ衬底上生长Ｇａ１－ｘＡｌｘＡｓ时，在界面处的失配位错少，...     

四元合金Ga_xIn_（1－x）As_（1－y）Sb_y的禁带宽度与组分关系的计

四元合金Ｇａ＿ｘＩｎ＿（１－ｘ）Ａｓ＿（１－ｙ）Ｓｂ＿ｙ的禁带宽度与组分关系的计算与讨论田园，张宝林，金亿鑫，周天明，李树纬，宁永强，蒋红，元光（中国科学院长春物理研究所，长春１３００２１）ＧａｌｎＡｓＳｂ是直接带隙、窄禁带的半导体材料，其波长范围为...     

BaSn＿（1－x）Sb＿xO＿（3－δ）和Ba＿（1－y）La＿ySnO＿（3－δ）的导电机制

测量了ＢａＳｎ＿（１－ｘ）Ｓｂ＿ｘＯ＿（３－δ）和Ｂａ＿（１－ｙ）Ｌａ＿ｙＳｎＯ＿（３－δ）样品的低温电阻率和磁化率．实验结果表明，在较低温度区域，两类样品的导电机制均是传导电子的范围可变跳跃。而在较高温度区域，ＢａＳｎ＿（１－ｘ）Ｓｂ＿ｘＯ＿（３－δ）样品的电导主要是电子从定域态到扩展态的跃迁所贡献，Ｂａ＿（１－ｙ）Ｌａ＿ｙＳｎＯ＿（３－δ）样品的电导则可能来源于电子的最近邻跳跃。     

Siδ掺杂Al＿xGa＿（1─x）As／GaAs异质结二维电子气的SdH振荡研究

使用分子束外延方法生长了一种新的基于Ｓｉδ掺杂的ＡｌｘＧａ＿１－ｘＡｓ／ＧａＡｓ异质结，测量了０．３－３０Ｋ低温下异质结处二维电子气的横向磁阻、迁移率和Ｈａｌｌ电阻，磁阻的Ｓｈｕｂｎｉ－ｋｏｖ－ｄｅＨａｓｓ（ＳｄＨ）振荡非常明显。对振荡曲线作快速Ｆｏｕｒｉｅｒ变换分析，获得了二维电子气中每一子能带上占据的电子数密度和有效质量（ｍ＿０／ｍ＿０＝０．０７３，ｍ＿１／ｍ＿０＝０．０６８）．随温度降低，子带上占据的电子增多，实验中发现：当样品温度为０．３Ｋ，横向磁场从０到７Ｔ扫描时，磁阻振荡出现间歇性的反常峰，磁阻振幅陡然增大５－６倍。     

Gd＿（1－x）Ca＿xBa＿2Cu＿3O＿（7－y）高温超导体压力效应的研究

研究了Ｇｄ＿（１－ｘ）Ｃａ＿ｘＢａ＿２Ｃｕ＿３Ｏ＿（７－ｙ）（０．０≤Ｘ≤０．２０）高温超导体在常压和高压下的超导电性在１－３００Ｋ温度范围内，利用Ｂｒｉｄｇｍａｎ对顶砧获得压力达９．０ＧＰａ，测量了（Ｘ＝０．１０，０．１５，０．２０）样品的ｄＴ＿ｃ／ｄｐ分别为７．６８，７．８和４．４６Ｋ／ＧＰａ。发现Ｔ＿ｃ的压力导数随着ｃａ￣（２＋）含量的增加而下降，分析了氧含量对Ｔ＿ｃ和ｄＴ＿ｃ／ｄＰ的影响．利用常压下晶格参数精修值和阳离子与氧离子间距随压力的改变，说明ＣｕＯ＿２面在超导电性上的作用，用ＣｕＯ＿２面之间耦合解释Ｔ＿ｃ（Ｐ）曲线的非线性关系。     

混晶GaAs_（1－x）P_x∶N中N_x发光的声子伴线结构

本文采用荧光窄化技术，对低组分的ＧａＡｓ（１－ｘ）Ｐｘ∶Ｎ（ｘ＝０．７６，０．６５）混晶材料中Ｎｘ束缚激子的声子伴线进行了研究．在低温下，选择激发Ｎｘ带时，我们得到了与ＧａＰ∶Ｎ低温发光谱中类似的声子伴线结构．根据实验结果，给出了混晶中各种声子的能量．另外，对组分为ｘ＝０．７６的ＧａＡｓ（１－ｘ）Ｐｘ∶Ｎ混晶样品，我们还首次观察并分析了多声子重现光谱．     

液相外延生长超薄有源层Al_xGa_（1－x）As／GaAs分别限制双异质结构激光器

报道超薄有源层ＡｌｘＧａ１－ｘＡＳ／ＧａＡｓ分别限制双异质结构半导体激光器的液相外延的过程。讨论了过冷度、生长温度和降温速率等对生长速率的影响。扫描电镜测得生长温度为６８０℃时，ＧａＡｓ有源层厚度可低至２５～３５ｎｍ。宽接触分别限制双异质结构ＬＤｓ的室温连续阈值电流密度多在７００～８００Ａ／ｃｍ２。     

MBE生长的In_(1-x-y)Ga_xAl_yAs/InP四元混晶的拉曼散射

ＭＢＥ生长的Ｉｎ１－ｘ－ｙＧａｘＡｌｙＡｓ／ＩｎＰ四元混晶的拉曼散射韩和相汪兆平李国华徐士杰刘南竹朱作明（中国科学院半导体研究所半导体超晶格国家重点实验室北京１０００８３）ＯｐｔｉｃａｌＰｈｏｎｏｎＲａｍａｎＳｃａｔｅｒｉｎｇｆｒｏｍＩｎ１－ｘ－ｙＧ...     

InxGa1－xAs缓冲层上InyGa1－yAs/(Al)Ga

本文中,发现在In_xGa_1-xAs缓冲层上非故意掺杂的In_yGa_1-yAs/(Al)GaAs超晶格样品中存在着两个互相反向的自建电场区,一个位于样品表面,另一个位于In_xGa_1-xAs缓冲层和超晶格界面。据此,合理地解释了样品的光伏测试结果,并对此类样品的MOCVD生长工艺给予指导。     

Breakdown voltage analysis of Al0.25Ga0.75N/GaN high electron mobility transistors with partial silicon doping in the AlGaN layer

In this paper,two-dimensional electron gas（2DEG） regions in AlGaN/GaN high electron mobility transistors（HEMTs） are realized by doping partial silicon into the AlGaN layer for the first time.A new electric field peak is introduced along the interface between the AlGaN and GaN buffer by the electric field modulation effect due to partial silicon positive charge.The high electric field near the gate for the complete silicon doping structure is effectively decreased,which makes the surface electric field uniform.The high electric field peak near the drain results from the potential difference between the surface and the depletion regions.Simulated breakdown curves that are the same as the test results are obtained for the first time by introducing an acceptor-like trap into the N-type GaN buffer.The proposed structure with partial silicon doping is better than the structure with complete silicon doping and conventional structures with the electric field plate near the drain.The breakdown voltage is improved from 296 V for the conventional structure to 400 V for the proposed one resulting from the uniform surface electric field.     

Breakdown voltage analysis of Al_0.25Ga_0.75N/GaN high electron mobility transistors with partial silicon doping in the AlGaN layer

In this paper,two-dimensional electron gas(2DEG) regions in AlGaN/GaN high electron mobility transistors(HEMTs) are realized by doping partial silicon into the AlGaN layer for the first time.A new electric field peak is introduced along the interface between the AlGaN and GaN buffer by the electric field modulation effect due to partial silicon positive charge.The high electric field near the gate for the complete silicon doping structure is effectively decreased,which makes the surface electric field uniform.The high electric field peak near the drain results from the potential difference between the surface and the depletion regions.Simulated breakdown curves that are the same as the test results are obtained for the first time by introducing an acceptor-like trap into the N-type GaN buffer.The proposed structure with partial silicon doping is better than the structure with complete silicon doping and conventional structures with the electric field plate near the drain.The breakdown voltage is improved from 296 V for the conventional structure to 400 V for the proposed one resulting from the uniform surface electric field.     

缓冲层对LBO晶体上1 064 nm,532 nm二倍频增透膜的激光损伤阈值的影响

采用电子束蒸发方法在LBO晶体上制备了无缓冲层和具有不同缓冲层的1 064 nm,532 nm二倍频增透膜.利用Lambda900分光光度计和调Q脉冲激光装置对样品的光学性能和抗激光损伤性能进行了测试分析.结果表明,所有样品在1 064 nm和532 nm波长的剩余反射率都分别小于0.1%和0.2%.与无缓冲层样品相比,采用SiO2和MgF2缓冲层薄膜的激光损伤阈值分别提高了23.1%和25.8%,而Al2O3缓冲层的插入却导致薄膜的激光损伤阈值降低.通过观察薄膜的激光损伤形貌,分析破斑的深度信息和电场分布,表明LBO晶体上1 064 nm,532 nm二倍频增透膜的激光损伤破坏主要表现为膜层剥落,激光产生的热冲击应力使薄膜应力发生很大变化,超过膜层之间的结合而引起膜层之间的分离.采用SiO2或MgF2缓冲层可改进Al2O3膜层的质量,从而有利于提高薄膜的激光损伤阈值.     

缓冲层对LBO晶体上1 064 nm|532 nm二倍频增透膜的激光损伤阈值的影响

采用电子束蒸发方法在LBO晶体上制备了无缓冲层和具有不同缓冲层的1 064 nm,532 nm二倍频增透膜.利用Lambda900分光光度计和调Q脉冲激光装置对样品的光学性能和抗激光损伤性能进行了测试分析.结果表明,所有样品在1 064 nm和532 nm波长的剩余反射率都分别小于0.1％和0.2％.与无缓冲层样品相比,采用SiO2和MgF2缓冲层薄膜的激光损伤阈值分别提高了23.1％和25.8％,而Al2O3缓冲层的插入却导致薄膜的激光损伤阈值降低.通过观察薄膜的激光损伤形貌,分析破斑的深度信息和电场分布,表明LBO晶体上1 064 nm,532 nm二倍频增透膜的激光损伤破坏主要表现为膜层剥落,激光产生的热冲击应力使薄膜应力发生很大变化,超过膜层之间的结合而引起膜层之间的分离.采用SiO2或MgF2缓冲层可改进Al2O3膜层的质量,从而有利于提高薄膜的激光损伤阈值.     

自旋轨道矩调控的垂直磁各向异性四态存储器结构

利用氧化钽缓冲层对垂直各向异性钴铂多层膜磁性的影响,构想并验证了一种四态存储器单元.存储器器件包含两个区域,其中一区域的钴铂多层膜[Pt(3 nm)/Co(0.47 nm)/Pt(1.5 nm)]直接生长在热氧化硅衬底上,另一个区域在磁性膜和衬底之间沉积了一层氧化钽作为缓冲层[TaO x(0.3 nm)/Pt(3 nm)/Co(0.47 nm)/Pt(1.5 nm)],缓冲层导致两个区域的垂直磁各向异性不同.在固定的水平磁场下对器件施加与磁场同向的电流,由于电流引起的自旋轨道耦合力矩,两个区域的磁化取向均会发生翻转,且拥有不同的临界翻转电流.改变通过器件导电通道的电流脉冲形式,器件的磁化状态可以在4个态之间切换.本文器件的结构为设计自旋轨道矩存储器件提供了新的思路.     

阶梯AlGaN外延新型Al_(0.25)Ga_(0.75)N/GaNHEMTs击穿特性分析

为了优化AlGaN/GaN HEMTs器件表面电场,提高击穿电压,本文首次提出了一种新型阶梯AlGaN/GaN HEMTs结构.新结构利用AlGaN/GaN异质结形成的2DEG浓度随外延AlGaN层厚度降低而减小的规律,通过减薄靠近栅边缘外延的AlGaN层,使沟道2DEG浓度分区,形成栅边缘低浓度2DEG区,低的2DEG使阶梯AlGaN交界出现新的电场峰,新电场峰的出现有效降低了栅边缘的高峰电场,优化了AlGaN/GaN HEMTs器件的表面电场分布,使器件击穿电压从传统结构的446 V,提高到新结构的640 V.为了获得与实际测试结果一致的击穿曲线,本文在GaN缓冲层中设定了一定浓度的受主型缺陷,通过仿真分析验证了国际上外延GaN缓冲层时掺入受主型离子的原因,并通过仿真分析获得了与实际测试结果一致的击穿曲线.     

InxGa1-xN/InyGa1-yN多量子阱结构 发光特性的测量与分析

利用MOCVD方法在蓝宝石衬底上生长了In_xGa_1-xN/In_yGa_1-yN多量子阱结构外延层,并用变温光致发光(PL)光谱、选择激发光谱以及激发(PLE)光谱等手段研究了该结构的量子效率、多峰效应的起源以及峰位随温度变化等信息。变温PL光谱的结果表明:在温度从30 K变化到300 K时,其峰值强度只下降了1.36倍且发光波长发生了蓝移。通过选择激发光谱证明了其发光峰位的独立性。PLE结果表明了GaN和势垒层的Stokes位移很小,但是In_xGa_1-xN阱层的Stokes位移变化很大。同时,提出了一种可同时获得多个吸收边的数据处理方法。     

Novel high-voltage power lateral MOSFET with adaptive buried electrodes

A new high-voltage and low-specific on-resistance (R on,sp ) adaptive buried electrode (ABE) silicon-on-insulator (SOI) power lateral MOSFET and its analytical model of the electric fields are proposed. The MOSFET features are that the electrodes are in the buried oxide (BOX) layer, the negative drain voltage V d is divided into many partial voltages and the output to the electrodes is in the buried oxide layer and the potentials on the electrodes change linearly from the drain to the source. Because the interface silicon layer potentials are lower than the neighboring electrode potentials, the electronic potential wells are formed above the electrode regions, and the hole potential wells are formed in the spacing of two neighbouring electrode regions. The interface hole concentration is much higher than the electron concentration through designing the buried layer electrode potentials. Based on the interface charge enhanced dielectric layer field theory, the electric field strength in the buried layer is enhanced. The vertical electric field E I and the breakdown voltage (BV) of ABE SOI are 545 V/μm and -587 V in the 50 μm long drift region and the 1 μm thick dielectric layer, and a low R on,sp is obtained. Furthermore, the structure also alleviates the self-heating effect (SHE). The analytical model matches the simulation results.     

Pre- and post-breakdown electrical studies in ultrathin Al2O3 films by conductive atomic force microscopy

The loss of local dielectric integrity in ultrathin Al₂O₃ films grown by atomic layer deposition is investigated using conducting atomic force microscopy. I–V spectra acquired at different regions of the samples by constant and ramping voltage stress are analyzed for their pre- and post-breakdown signatures. Based on these observations, the thickness dependent dielectric reliability and failure mechanism are discussed. Our results show that remarkable enhancement in breakdown electric field as high as 130 MV/cm is observed for ultrathin films of thickness less than 1 nm.