改变金扩散程序增强扩金效果

本文综述了金在硅中的异常扩散行为,重点分析了高浓度磷扩散区对金的吸收作用和SiO_2,对金原子扩散的掩蔽作用.指出目前逻辑集成电路制造中广泛采用的金扩散程序,其扩金效果较差,提出金扩散与磷扩散同时进行的新扩金程序.实验结果证实扩金效果得到增强,从而开关性能相应得到改善.     

一种新的磷扩散源——固体磷源及其在泡发射极中的应用

本文介绍了一种用固态磷扩散源作磷扩散的工艺方法与反应机理,工艺设备及扩散条件与结构参数的关系,同时实验地确定了该扩散工艺方法中磷掺杂浓度的分布情况。并说明了该磷扩散方法的一个突出优点,即可以运用于泡发射极工艺。     

新型片状磷平面扩散源的应用研究

分析了新型片状固态磷平面扩散源(PDS)的掺杂机理,并与液态POCl3源扩散进行了比较,指出可用片状固态磷PDS来替代POCl3实现磷扩散工艺的预沉积。基于PDS预沉积的实验结果,分析了影响方块电阻大小及其均匀性的关键因素,给出了工艺方案,并通过实际产品的电学参数测量结果验证了工艺方案的可行性,可供新型片状磷PDS在大直径硅扩散工艺中的推广使用参考。     

温度梯度下磷在硅中的扩散

在单晶硅本身存在温度梯度条件下，实验观察到施主杂质磷在硅中的扩散系数比在恒温扩散炉条件下的扩散系数大得多。文中对这种异常扩散现象进行了讨论。     

3CG110型三极管无浓磷扩散工艺

在pnp型硅平面系列三极管制造过程中,基区扩散通常由浓磷扩散和淡磷扩散两部分组成.由于工艺复杂,工序繁多,而使器件的成品率一直不高.本文提出了一种无浓磷扩散的新方法,较好地解决了这一问题.通过一年左右的生产实践,证明此方法是可行的,效果是显著的,可使3CG110的管芯成品率提高8～10%.     

片状磷源的扩散

一、前言 磷扩散是半导体器件和集成电路的基本工艺之一,磷扩散的分布状况对半导体器件和集成电路的性能、成品率有很大影响。半导体集成电路的集成度已发展到扩散条宽为2～3微米的大规模、超大规模集成电路,对磷扩散掺杂的精确控制,均匀性和重复性,提出了更高的要求,常用的液态三氯氧磷源不能完全满足这些需要。研究和发展新的磷扩散源,是国内外半导体工业普遍重视的问题。 一九六七年RCA公司发明用片状氮化硼作扩散源有许多优越性以来,人们就开始研究和发展片状磷源,到一九七六年美国Owens-Illinois公司发表了片状磷源的专     

磷予淀积中杂质分布的工艺控制

本文通过磷表面浓度,磷结深度和磷源与磷分布之间联系的建立,揭示在磷扩的工艺控制中扩散温度、扩散时间、通源量和气氛等工艺因素对杂质分布的作用。     

高浓度磷扩散的模拟

介绍了在SilvacoTCAD软件中最新加入的磷扩散模型──PERCO模型。该模型建立了杂质、空位及自间隙的连续性方程，描述了由于高浓度磷扩衡引起的超平衡点缺陷对磷在硅中分布的影响。已将该模型用于对实际工艺模拟的校正，取得满意的结果，同时，可以体会到模型校正的意义。     

提高三重扩散结深的途径

提高三重扩散结深的途径为弥补一重扩散晶体管的某些不足，人们研制了“三重扩散晶体管”。它是用高浓度磷衬底Ｎ＋代替高阻区Ｎ，以减少硅片厚度，获得较低的饱和压降，改善大电流特性，同时提高抗二次击穿的能力。三重扩散的制作方法是这样的：去除Ｓｉ片表面可能残留着...     

片状固态扩散源在磷扩散工艺中的应用

本文介绍了采用国产的片状固态磷扩散源所进行的磷扩散工艺实验及其结果。有效成分为偏磷酸铝和焦磷酸硅的磷源片具有无毒、贮运方便等优点,固态源扩散的系统简单,操作容易。实验的结果表明,扩散结深、扩散薄层电阻、结的击穿电压等参数均能满足常规硅平面工艺的要求,扩散的均匀性也是令人满足的。     

A method for low-concentration phosphorus diffusion by ambient control

A method of surface concentration control for phosphorus diffusion by manipulating the growth rate of phosphosilicate glass is described. It is pointed out that the surface concentration in the oxidising ambient can be varied over a wide range by changing (i) the ratio of partial pressures of oxygen and dopant, and (ii) the diffusion temperature. Experimental results for phosphorus diffusion in oxidising ambient using PH₃ source at various diffusion temperatures are presented.     

Estimation of effective diffusion time in a rapid thermal diffusionusing a solid diffusion source

Two-step rapid thermal diffusion (RTD) of phosphorus and boron using a solid diffusion source is described. From the application of the Boltzmann-Matano method to SIMS profiles of phosphorus and boron after RTD, it has been found that some additional correction terms to the effective diffusion time must be introduced. In the phosphorus diffusion case, the increment of the effective diffusion time due to the supersaturation of point defects during the cooling cycle is about 3 s. In the case of boron diffusion, the additional effective diffusion time is a strong function of diffusion temperature. This has been explained as the effect of initial growth of the boron-rich layer during the glass-transfer process. The introduction of additional correction terms to the effective diffusion time makes it possible to treat the RTD process in a similar manner to normal diffusion     

A model of high-and low-temperature phosphorus diffusion in silicon by a dual pair mechanism

A model of phosphorus diffusion in silicon was developed on the basis of a dual pair mechanism; according to this model, the contribution of the impurity-vacancy (PV) and impurity-self-interstitial (PI) pairs to diffusion is accounted for directly in terms of the phosphorus diffusion coefficient. A violation of thermodynamic equilibrium in relation to native point defects occurs as a result of diffusion of the PI neutral pairs. At the high-temperature diffusion stage, the phosphorus diffusion is described by a single diffusion equation with the diffusion coefficient dependent on both the local and surface phosphorus concentrations; whereas at the next (occurring at lower temperatures) stage, the phosphorus diffusion is described by two diffusion equations for the total concentrations of the components containing phosphorus and self-interstitials. An anomalously high rate of the low-temperature diffusion is ensured by excess self-interstitials accumulated in the doped layer during the preceding high-temperature diffusion. The model makes it possible to quantitatively account for the special features of the phosphorus diffusion in a wide range of the surface concentrations at both the high (900–1100°C) and lower (500–700°C) temperatures.     

Elimination of emitter edge dislocations in silicon planar n-p-n transistors

It is shown that the conventional method for elimination of emitter edge dislocations, which consists of a low concentration emitter phosphorus diffusion, has two disadvantages: it increases reverse emitter-base current and reduces current gain at low currents. Also, it is shown that the mentioned disadvantages can be successfully avoided by a new method for elimination of emitter edge dislocations, which consists of a high concentration emitter phosphorus diffusion followed by an additional shallow boron diffusion.     

硼和磷离子注入硅中的异常载流子剖面分布

观察了硼和磷离子注入 Si 中的载流子浓度剖面分布和异常增强扩散。将不同注入能量、不同剂量、常规退火和快速退火得到的结果进行了此较。结果表明:(1)对剂量小于或等于10~(14)cm~(-2)的硼离子注入,没观察到异常的载流子剖面分布。随着剂量的增加,将出现异常增强扩散尾;(2)不管退火方法如何,在磷离子注入中观察到了异常的载流子剖面分布和增强扩散尾。     

Approximations to two-step diffusion process by Prony's method

A simple two-term approximation that is accurate over a wide range of drive-in ratios is given for the two-step diffusion process. Comparison with earlier approximations are graphically given. The final approximation is simple and convenient in evaluating the device performance. The Prony's method adopted to approximate erfc(x) is useful in approximating other profiles as well, such as anomalous diffusion profile of phosphorus, ion-implanted profile, etc.     

Preparation of n+ emitter on p-type silicon wafer using the spin-on doping method

There is a strong need for cost reduction in manufacturing crystalline silicon solar cells, and one of the approaches is to merge two steps of silicon wafer processing into one step without degrading the performance of solar cells. In this work, we intended to employ the spin-on doping (SOD) method for the purpose of dual tasks, phosphorus diffusion to form n⁺ emitters and antireflection coating (ARC) to reduce optical reflection. Different from the commercial SOD solutions based on SiO₂, we used tetraethylorthosilicate (TEOS) to prepare SOD solutions containing different concentrations of phosphorus acid as the phosphorus doping source. We first investigated the dependence of the sheet resistance of the n⁺ emitters on the concentration of phosphorus acid in the SOD solution as well as the thermal diffusion temperature and time. It was found that all these three factors can effectively influence the sheet resistance of the n⁺ emitters, suggesting a relatively easier optimization process for forming n⁺ emitters using the SOD method. The SOD thin films formed after the thermal diffusion process were found to be SiO₂ films. We then investigated the antireflection properties of the as-grown SOD thin films, and found that they can effectively reduce the optical reflection of silicon wafers.     

Observations on phosphorus stabilized SiO2films

Two experiments were performed with phosphorus stabilized and untreated silicon dioxide films on silicon substrates. In the first, the interaction of phosphorus and boron was studied; it was found that diffusion of boron over a phosphorus stabilized film destroyed its stabilization against ion drift effects at 400°C, but that diffusion of phosphorus over a boron diffused film resulted in a stabilized oxide. In the second experiment, a slowly varying voltage was applied at 600°C to a silicon-silicon dioxide-gold structure and the current through the oxide film was recorded. Both phosphorus stabilized and untreated silicon dioxide films show rectifying characteristics, the more highly conducting direction being that with the silicon negative. In the case of the untreated film, a large peak of current is superimposed on this characteristic at -2.5 volts. This peak is absent in phosphorus stabilized films. Discharge currents equivalent to the charging currents are not observed on removing voltage from the specimen, as they are at 400°C. Five distinguishable types of charge transfer in silicon dioxide films are tabulated, and compared with those described in the literature as occurring in crystal quartz.     

Silicon nitride as a mask in phosphorus diffusion

By means of tracer and activation experiments it is shown that during phosphorus diffusion in silicon nitride diffusion profiles are produced, which are very similar to the profiles in silicon dioxide processed in the same experiment. When oxygen was used as part of the carrier gas as is customary in semiconductor technology, a glass was produced in both cases which consisted of SiO₂ and P₂O₅ and whose identity was proved by i.r. absorption and determination of the refractive index. When the medium does not contain oxygen, part of the nitride is transformed to silicon phosphide which is incorporated in the glass or escapes at higher temperatures. When oxygen is present, the silicon phosphide occurs briefly in an intermediate reaction. In this way the normal, slow oxidation of the nitride is accelerated and phosphorus pentoxide acts as a catalyst. The analogous formation of glass from oxide and nitride is the reason why silicon nitride exhibits a similar masking effect as silicon dioxide in phosphorus diffusion, even though it masks better than silicon dioxide against the diffusion of a number of other elements.