GaAs的CH_4／H_2反应离子腐蚀研究

在前研究ＩｎＰ的ＣＨ４／Ｈ２反应离子腐蚀的基础上，进行了ＧａＡｓ的ＣＨ４／Ｈ２反应离子腐蚀研究。ＧａＡｓ的腐蚀速率比ＩｎＰ慢，随ＣＨ４／Ｈ２组份之比值、工作压强、总流量率等而改变，从２ｎｍ／ｍｉｎ到８ｎｍ／ｍｉｎ。当总流量率为３０～１２３ｓｃｃｍ之间、ＣＨ４／Ｈ２＝０．１８，腐蚀后的表面总是光亮平滑的，损伤层的厚度≥３０ｎｍ。当用ＣＨ４／Ｈ２ＲＩＥ在ＣａＡｓ上制作深度＞０．６μｍ的结构时，必须要考虑高能离子的轰击给晶体造成的损伤和给光刻胶掩模造成的浸蚀，此时光刻胶作掩模已经不能满足要求，应改用介质薄膜。     

GaAs、GaP、InP、InGaAsP、AlGaAs、InAlGaAs的化学腐蚀研究

为研制全集成光开关、微片式激光器等，对ＧａＡｓ、ＧａＰ、ＩｎＧａＡｓＰ、ＩｎＡＩＧａＡｓ、ＡｌＧａＡｓ等材料的化学腐蚀进行了实验研究。为了研制ＩｎＡｌＧａＡｓ／ＩｎＡｌＡｓ／ＩｎＡｌＧａＡｓ微片式激光器，开发了Ｈ３ＰＯ４／Ｈ２Ｏ２／Ｈ２Ｏ薄层腐蚀液和ＨＣｌ／Ｈ２Ｏ选择性腐蚀液；为了研制ＩｎＧａＡｓＰ／ＩｎＰ／ＩｎＧａＡｓＰＴｂａｒ型光波导，开发了ＨＣｌ／Ｈ３ＰＯ４／Ｈ２Ｏ２薄层腐蚀液和ＨＣｌ／Ｈ２Ｏ２选择性腐蚀液；为了研制ＧａＰ、ＩｎＧａＰ光波导，开发了ＨＣｌ／ＨＮＯ３／Ｈ２Ｏ薄层腐蚀液。它们都具有稳定、重复性好、速率可控、腐蚀后表面形貌好等特点。除此之外，蚀刻成的ＧａＰ光波导侧壁平滑无波纹起伏。此种结果尚未见报导。     

Sol-Gel法制备的铁电薄膜和Pt/Ti下电极的反应离子刻蚀技术

为制备Ａ１／ＰＺＴ／Ｐｔ／Ｔｉ电容,研究了采用ＳＦ６／Ａｒ等离子体对Ｐｂ（Ｚｒ,Ｔｉ）Ｏ３及Ｐｔ／Ｔｉ底电极进行反应离子刻蚀（ＲＩＥ）的技术．较系统地研究了ＲＦ功率,ＳＦ６／Ａｒ流量比及气压对刻蚀速率的影响,找到了对ＰＺＴ及Ｔｉ进行ＲＩＥ的优化工艺条件．在不同的条件下得到对ＰＺＴ的刻蚀速率为２～７ｎｍ／ｍｉｎ;采用纯Ａｒ气体时Ｐｔ的刻蚀速率为２～６ｎｍ／ｍｉｎ;对于Ｔｉ可用ＨＣｌ及Ｈ２Ｏ２溶液进行腐蚀     

GaAs衬底层选择性腐蚀技术

本文在ＧａＡｓＧａＡｌＡｓ选择性腐蚀的基础上进行了腐蚀ＧａＡｓ衬底层获得ＧａＡ／ＧａＡｌＡｓ外延层薄膜的二次腐蚀技术。最终选用了Ｃ３Ｈ４（ＯＨ）（ＣＯＯＨ）３．Ｈ２Ｏ－Ｈ２Ｏ２系选择性腐蚀液和Ｈ２ＳＯ４－Ｈ２Ｏ２系腐蚀液，获得了快速，可控制，重复性好的可全部可局部去除衬底的腐蚀方法。     

AlInAs／GaINAsHBTIC技术

本文描述了用与ＩｎＰ衬底晶格匹配的ＡｌＩｎＡｓ／ＧａＩｎＡｓ异质结双极晶体管制作的集成电路。ＨＢＴ的发射极尺寸为２μｍ×５μｍ，截止频率ｆ＿Ｔ和最高振荡频率ｆ＿ｍａｘ分别为９０ＧＨｚ和７０ＧＨｚ。用电流型逻辑（ＣＭＬ）制作了环形振荡器、触发器分频电路和双模前置换算器。其环形振荡器每门延迟时间为１５．８ｐｓ，ＣＭＬ触发器分频电路反转速率为２４．８ＧＨｚ。而４／５和８／９双模前置换算器分别由１０６和１２４只晶体管组成，可在高达９ＧＨｚ的时钟速率下工作。这两种双模前置换算器电路是ＩｎＰ基Ｈ８Ｔ制作的最大规模电路。     

硅表面清洗对7nm热SiO_2栅介质可靠性的影响

实验研究了硅表面清洗方式对７ｎｍ热氧化ＳｉＯ２栅介质可靠性的影响．结果表明,稀ＨＦ酸漂洗后ＲＣＡ清洗时降低ＳＣ１（ＮＨ４ＯＨ／Ｈ２Ｏ２／Ｈ２Ｏ）温度对提高栅介质可靠性有利,但仍不如用ＳＣ２（ＨＣｌ／Ｈ２Ｏ２／Ｈ２Ｏ）或Ｈ２ＳＯ４／Ｈ２Ｏ２清洗效果好．稀ＨＦ酸漂洗后用Ｈ２ＳＯ４／Ｈ２Ｏ２清洗得到的栅介质不仅表现出优良的击穿电场分布特性和击穿电荷分布特性,抗热电子损伤能力也比较强     

AlSiCu反应离子刻蚀技术

在Ｔｅｇａｌ１５１２ｅ反应离子刻蚀（ＲＩＥ）设备上，利用Ｃｌ＿２和ＳｉＣｌ＿４为主要刻蚀气体，进行了ＡｌＳｉ０．８％－Ｃｕ２％的ＲＩＥ工艺研究，详细讨论了影响工艺的诸多因素，涉及ＡｌＳｉＣｕ材料本身结构的差异，ＲＩＥ工艺各参数，后处理等许多方面；给出实用化的工艺程序；最小加工线宽达到２μｍ，体刻蚀速率达８７０ｎｍ／ｍｉｎ，均匀性±５％，线宽损失小于１０％，对热氧化ＳｉＯ＿２的刻蚀选择比为４∶１，对ＡＺ１４５０Ｊ正性抗蚀剂的刻蚀选择比大于１．８∶１；该工艺使用效果良好，达到实用化水平。     

铁基SiN表面陶瓷的结构及耐酸性腐蚀行为

研究了铁基表面镀硅（～５０ｎｍ 厚）经氮离子束处理（能量为 ４０ｋｅ Ｖ,剂量分别为５×１０１６,１×１０１７,５×１０１７ｃｍ － ２）后的表面结构和在 １ Ｎ Ｈ２ Ｓ Ｏ４ 水溶液中的腐蚀行为。 Ｔ Ｅ Ｍ 证明,各试样表面均存在一完整的非晶层;电化学测量和失重实验表明,试样的失重量与浸泡时间满足幂函数规律;经表面处理过的试样,腐蚀电位提高了 ３０～４０ｍ Ｖ,腐蚀电流密度下降了 ４～６ 倍;耐腐蚀性随氮离子剂量的增大而不断提高。文章还结合腐蚀表面的粗糙度（分形维数）讨论了离子注入对表面结构和耐蚀性的影响。     

同步辐射光电子能谱研究室温下Na对InP（100）表面氮化反应的影响

利用同步辐射光电子能谱研究了室温下Ｎａ吸附下于Ｐ型ＩｎＰ（１００）表面对其氮化反应的影响．通过Ｐ２ｐ、Ｉｎ４ｄ芯能级谱的变化，对Ｎａ／ＩｎＰ（１００）表面的氮化反应的研究表明，碱金属Ｎａ的吸附对ＩｎＰ（１００）无明显的催化氮化作用，即使采用Ｎ２／Ｎａ／Ｎ２／Ｎａ／Ｎ２／Ｎａ／ＩｎＰ（１００）的类多层结构，在室温下也只有极少量的氨化物形成，而无明显的催化氮化反应发生．碱金属吸附层对Ⅲ－Ⅴ族半导体氮化反应的催化机制不同于碱金属对于元素半导体的催化反应机制，碱金属对元素半导体的催化氮化反应，吸附的碱金属与元素半     

2.4μm GaInAsSb红外探测器台面腐蚀研究

本文提出了适于２．４μｍ ＧａＩｎＡｓＳｂ台面结构探测器制备的ＨＦ／Ｈ２Ｏ２／Ｃ４Ｈ６Ｏ６／Ｈ２Ｏ腐蚀液体系,并确定了合适的成分配比。实验结果表明,该腐蚀液体系对ＧａＩｎＡｓＳｂ材料腐蚀速度适中、侧向腐蚀小、不破坏光刻胶保护、腐蚀面平整、腐蚀槽齐整、受外延片表面质量影响较小。     

Etching of silicon carbide for device fabrication and through via-hole formation

We have investigated the etching of SiC using inductively-coupled-plasma reactive ion etching with SF₆-based and Cl₂-based gas mixtures. Etch rates have been investigated as functions of bias voltage, ICP coil power, and chamber pressure. It will be shown, for the first time, that SiC surfaces etched in Cl₂-based plasmas yield better surface electrical characteristics than those etched in SF₆-based plasmas. We have also achieved SiC etch rates in excess of 1 μm/min which are suitable for micro-machining and via-hole applications. Through via-holes obtained in 140 μm thick SiC at an effective etch rate of 824 nm/min have been achieved. To the best of our knowledge, to date, this is the highest effective etch rate for a through via-hole etched with a masking process compatible with microelectronic fabrication.     

Chemically assisted ion beam etching of gallium nitride

Chemically assisted ion beam etching of gallium nitride (GaN) grown by metalorganic chemical vapor deposition has been characterized using an Ar ion beam and Cl₂gas. The etch rate of GaN was found to increase linearly with Ar ion beam current density, increase linearly then saturate with Ar ion beam energy, vary slightly with Cl₂ flow rate, and lastly, increase moderately with substrate temperature. Etch rates as high as 330 nm/min were obtained at high beam energies and 210 nm/min at a more nominal level of 500 eV. The anisotropy of etched profiles improved in the presence of Cl₂ in comparison to those etched by Ar ion milling only. Elevated substrate temperatures further enhanced the anisotropy to obtain near-vertical profiles for fairly deep-etched structures. Auger electron spectroscopy was used to investigate etch-induced surface changes. Oxygen contamination was observed on the as-etched surface but a dilute HC1 treatment restored the stoichiometry of the material to its unetched state.     

Dry etching of InGaAlP alloys in Cl2/Ar high ion density plasmas

Etch rates above 1 μm min⁻¹ are achieved for InGaP and AlInP under electron cyclotron resonance conditions in low pressure (1.5 mTorr) Cl₂/Ar discharges. Much lower rates were obtained for AlGaP due to the greater difficulty of the bond breaking that must precede formation and desorption of the etch products. The etched surface morphology and stoichiometry are strong functions of the plasma composition (i.e., the ion/neutral flux ratio). Under optimal conditions, there are no detectable chlorine related residues, in sharp contrast to reactive ion etching with this plasma chemistry.     

Bromine ion-beam-assisted etching of III–V semiconductors

Bromineion-beam-assisted etching produces smooth vertical sidewalls in GaAs, GaP, InP, AlSb, and GaSb as well as in the usual alloys formed from these materials. Care must be taken, however, during etching to match the specific material system with an appropriate substrate etch temperature. For example, vertical walls were obtained using substrate temperatures in the range of 150 to 200°C with InP, 80 to 140°C with GaAs and GaP, and below 30°C with AlSb and GaSb. GaN has also been etched with the technique. Our etching experience and the vapor pressure data for bromine with group III and group V elements lead us to believe that all of the various technologically important III-V binaries, ternaries, and quaternaries can be etched. Etch rates of most of the materials can be varied from several nm/min to 0.16 μm/min through the bromine flow rate, Ar⁺ ion beam density and energy, and the substrate temperature. Bromine ion-beam-assisted etching also appears to have an advantage over chlorine ion-beam-assisted etching in many situations, in that substrate temperature ranges can be found for which vertical sidewalls are maintained while etching through layered structures composed of various alloys of the materials. Here we present results obtained from etching a number of III-V binaries, alloys, and heterostructures.     

Reactive sputter etching of Al in BCl3

Etching of Al is studied in pure BCl₃ as well as in mixtures with other gases in the reactive sputter etching mode in a cryopumped system. Etch rate, selectivity with respect to positive photoresist, SiO₂ and Si and etch profiles are investigated as a function of gas composition, gas pressure, flow rate and plasma power. Plasma chemical processes are monitored by quadrupole mass spectroscopy as well as by optical emission spectroscopy. Perfectly square Al-profiles can be etched if etch rates are kept below 1000 A/min. Al-patterns running over steep steps can also be clearly defined if a certain amount of overetching can be tolerated. The experimental data indicate that the etch process is reactant supply limited. Anisotropic etching is achieved by either a ‘surface inhibitor mechanism’ or the formation of a sidewall protecting film.     

Reactive Ion Etching of GaAs, GaSb, InP and InAs in Cl2／Ar Plasma

Reactive ion etching characteristics of GaAs,GaSb,InP and InAs using Cl_2/Ar plasma have been investigated,it is that,etching rates and etching profiles as functions of etching time,gas flow ratio and RF power.Etch rates of above 0.45 μm/min and 1.2 μm/min have been obtained in etching of GaAs and GaSb respectively, while very slow etch rates (<40 nm/min) were observed in etching of In-containing materials,which were linearly increased with the applied RF power.Etched surfaces have remained smooth over a wide range of plasma conditions in the etching of GaAs,InP and InAs,however,were partly blackened in etching of GaSb due to a rough appearance.     

InSb阵列探测芯片的感应耦合等离子反应刻蚀研究

利用感应耦合等离子（ICP）反应刻蚀（RIE）进行了InSb阵列芯片台面刻蚀,并利用轮廓仪、SEM及XRD对台面形貌以及刻蚀损伤进行分析。采用优化的ICP刻蚀参数,实现的刻蚀速率为70~90 nm/min,刻蚀台阶垂直度~80°,刻蚀表面平整光滑、损伤低。与常规的湿法腐蚀相比,明显降低了侧向钻蚀。台面采用此反应刻蚀工艺,制备了具有理想I-V特性的320×256 InSb探测阵列芯片,在-500 mV到零偏压范围内,光敏元（面积23 μm×23 μm）的动态阻抗（Rd）大于100 MΩ。     

Chemical beam etching of InP in GSMBE

Etching of InP using a beam of PC1₃ is demonstrated in a standard gas source molecular beam epitaxy machine. The principle of an atomic layer accurate end-point detection technique usingin-situ reflection high energy electron diffrac-tion is described and used to study the kinetics of PCl₃ etching. The etch rate is found proportional to the PCI₃ fluence and weakly dependent on the substrate temperature. The morphology of etched surfaces and the etch rate uniformity is compatible with the regrowth of high quality InGaAsP active structures and with the realization of etch and regrowth sequences controlled at the nm scale. Etch profiles at mask edges are defined by nearly perfect crystallographic facets with a very limited mask undercut (≈100 nm) due to the beam nature of the etching technique.