Difference Between Diffusion and Ion Implantation

Diffusion vs Ion Implantation

扩散和之间的区别离子注入can be understood once you understand what diffusion and ion implantation is. First of all, it should be mentioned that diffusion and ion implantation are two terms related to半导体. They are the techniques used to introduce dopant atoms into semiconductors. This article is about the two processes, their major differences, advantages, and disadvantages.

什么是扩散？

扩散是用于将杂质引入半导体的主要技术之一。该方法考虑了掺杂剂在原子尺度上的运动，并且基本上，由于浓度梯度而发生的过程。扩散过程是在称为“diffusion furnaces”. It is fairly expensive and very accurate.

There arethree main sources of dopants: gaseous, liquid, and solids and the气态来源是该技术中最广泛使用的一种（可靠且方便的来源：BF₃, PH₃, AsH₃). In this process, the source gas reacts with oxygen on the wafer surface resulting in a dopant oxide. Next, it diffuses into Silicon, forming an uniform dopant concentration across the surface.液体来源are available in two forms: bubblers and spin on dopant. Bubblers convert liquid into a vapour to react with oxygen and then to form a dopant oxide on the wafer surface. Spin on dopants are solutions of drying form doped SiO₂layers.Solid sourcesinclude two forms: tablet or granular form and disc or wafer form. Boron nitride (BN) discs are most commonly used solid source that can be oxidized at 750 – 1100⁰C.

什么是离子植入？

Ion implantation is another technique of introducing impurities (dopants) to semiconductors. It is a low-temperature technique. This is considered as an alternative to high-temperature diffusion for introducing dopants. In this process, a beam of highly energetic ions is aimed at the target semiconductor. The collisions of the ions with the晶格原子导致失真晶体结构. The next step is annealing, which is followed to rectify the distortion problem.

Some advantages of the ion implantation technique include precise control of depth profile and dosage, less sensitive to surface cleaning procedures, and it has a wide selection of mask materials such as photoresist, poly-Si, oxides, and metal.

扩散和离子植入之间有什么区别？

• In diffusion, particles are spread through random motion from higher concentration regions to regions of lower concentration. Ion implantation involves the bombardment of the substrate with ions, accelerating to higher velocities.

•Advantages:Diffusion creates no damage and batch fabrication is also possible. Ion implantation is a low-temperature process. It allows you to control the precise dose and the depth. Ion implantation is also possible through the thin layers of oxides and nitrides. It also includes short process times.

•Disadvantages:扩散仅限于实心溶解度这是一个高温过程。浅连接处和低剂量很难扩散。离子植入涉及退火过程的广告成本。

•扩散有一个isotropicdopant profile whereas ion implantation has an各向异性dopant profile.

Summary:

Ion Implantation vs Diffusion

扩散和离子植入是将杂质引入半导体的两种方法（硅– Si) to control the majority type of the carrier and the resistivity of layers. In diffusion, dopant atoms move from surface into Silicon by means of the concentration gradient. It is via substitutional or interstitial diffusion mechanisms. In ion implantation, dopant atoms are added forcefully into Silicon by injecting an energetic ion beam. Diffusion is a high-temperature process while ion implantation is a low-temperature process. Dopant concentration and the junction depth can be controlled in ion implantation , but it cannot be controlled in the diffusion process. Diffusion has an isotropic dopant profile whereas ion implantation has an anisotropic dopant profile.

图像提供：

1. Simple diffusion of a substance (blue) due to a concentration gradient across a semi-permeable membrane (pink)byElizabeth2424(CC BY-SA 3.0)