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扫描电子显微镜

Scanning Electron Microscope

 
 
 
 
 

日志

 
 

电子显微镜应用之:微电子器件LED,Chip,SAW  

2011-08-15 11:11:32|  分类: 默认分类 |  标签: |举报 |字号 订阅

  下载LOFTER 我的照片书  |

 翻译 :  驰奔 (转载请注明)

We are Andrew Heap and Matthew Rzepka, and are undertaking a project to see what is inside a mobile phone. We will be using macro photography, optical microscopy, scanning electron microscopy and transmission electron microscopy.
Over the next few months we willl be working on this project and adding to the webpage as we go.
我们是安德鲁和马修,正在承担一个计划,看看手机里是什么。我们将使用显微摄影技术,光学显微镜,扫描电子显微镜,透射电子显微镜。
经过下面的几个月,我们将致力于这个计划并且将我们的进展加入到网页中。 翻译  驰奔 COXEM中国代表处 (转载请注明)

The mobile phone we are examing is a Nokia 3310. It is almost 10 years old, but was the basis for many future phones to be built upon on.

我们测试的手机是诺基亚3310型,几乎有10年了,但是许多未来手机也是在这个基础上设计的。

phone

A nokia 3310 phone 一个诺基亚3310手机
We first took the back cover off the phone, and uncovered the ciruit board, and removed any metal protective covers. We then highlighted the components of the phone, and chose to investigate the ones which would be most intresting to find out more about, and examine in much higher detail and magnfication. The first component we examined was one of the Light Emitting Diodes behind the keypad, and after that, we looked at one of the Microchips. After examining these components, we would decide which components woud be most interesting to investigate, and chose them.
我们首先打开手机后盖,揭露电路板,去掉金属保护层。我们于是突出手机的元件,选择那些可以找到更多感兴趣和有更多细节可检测,可以放大放大的作为调查对象。我们检测的第一个元件是键盘后面的发光二极管之一,随后我们着眼于一个微芯片。检测完这些元件后,我们将决定那些元件对对调查最令人感兴趣,我们就选择他们。

Light Emitting Diode发光二极管

After removing the cover of the phone, and examining the circuit board, we decided to examine one of the components in more detail. We first chose one of the Light Emitting Diodes. These were primarily used to light up the key pad when pressed, and light up when a call is being recieved. 
      去除手机封盖后,检查电路板,我们决定更详细的检查一个元件。我们首先选择了一个发光二极管。这个主要用于,在摁键盘时和在收到电话时照亮键盘.
We first removed one of the LEDs from the circuit board, and placed on a new circuit board so we can examine it more easily. 我们首先从电路板上拆下一个LED, 安放在一个新的电路板中以便我们可以更容易的检测

Light Emitting Diode

The LED under an Optical Microscope.光学显微镜下的LED

To check that the LED still worked, we placed it under the optical microscope, and passed various voltages across it, to see if would light up, and still behave how an LED should. Below are the photos taken at various voltages.
       核查这个LED仍然可以工作,我们把它放在光学显微镜下,给它通过各种电压,看是否点亮,是否和LED表现相同。下面是在不太难过电压下的照片。

   LED with 0 volts    LED with 2 volts    LED with 4 volts  

0 Volts                               2 Volts                                4 Volts

  6v.jpg    LED with 8 volts 

                         6 Volts                          8 Volts                          

Here we can see the LED behaving as we would expect, with noticeable amounts of light being given off once around 3 volts are passed across the LED.
      这里我们能看到LED表现符合我们的预期,一旦超过3v电压通过LED,显而易见的发出大量光.

We then placed the LED in the Scanning Electron Microscope, to examine in more detail and try to identify which elements it was made of.

      我们于是把LED放在扫描电镜中,检测更多细节,试着鉴定其组成成分。

Light Emitting Diode under SEM
LED在SEM下

After examing the LED under an optical microscope, we placed it in the Scanning Electron Microscope, to examine it in further detail, and to try to identify the elements it was made of. 在光学显微镜下检测LED后,我们使用扫描电镜,进一步检测它的细节,鉴定组成元素成分。

  led01.tif

We then used X-ray analysis to try and identify the elements in the LED and this showed us that the LED was Gallium Phosphide. This agreed with our early photos of green light being given off by the LED, as a Pure GaP LED would emit green light, with a wavelength of around 555 nm.
       我们于是使用X-ray(EDS)分析,试着鉴定LED中的元素,显示LED是镓磷化物。这个和之前的LED发出的绿光图像相符合,因为纯的GaP LED将发射波长大约为555nm的绿光,
LED

We could see a definitive line in the side of the LED after we turned it over, and we chose to investigate this further, to see if we could see any difference in the materials either side of this line. We perfomed a 'line scan' across the line, but did not find any difference in the concentrations. This is either down to the fact that there was no difference in the elements either side of the line, or if there were a difference, we probably would not detect it, as it is only a very small amount of doping.
       我们将样品旋转90°后,我们看到一条确定线在LED侧面,我们选择这个进一步调查,看看这条线的每一面的材料中是否有区别。我们通过这个线执行了一个线扫描程序,但是在关注点上没有发现任何区别。这个确定一个事实,线的任何一面元素成分没有差别,或者如果有差别,我们可能也探测器不到,因为它只有非常少量的掺杂。

LED side view


Light Emitting Diode under TEM
在透射电子显微镜TEM下的LED

After examining the LED in the Scanning Electron Microscope, we would examine using the Transmission Electron Microscope. Before we could examine it however, the LED had to be prepared so that it would work under the TEM. This required sanding and milling it down to less than a few microns thick. 
     测完SEM,我们使用TEM检查。在检测前,需要先制备LED,以适合TEM检测需要。这需要砂纸打磨,研磨直到小于几个微米厚。

LED prepared for TEM under optical microscope

LED, less than a few microns thick. 小于几个微米厚的LED


One can see how thin the sample is around the edges, where interference patterns appear, caused from the light bouncing off the back of the sample and interfering with the light bounding of the surface of the sample. This tells us that the sample is as thick as the wavelength of light, or several multiples of the wavelength at that point. The sample has to be this thin, for the TEM to work.

一个可以看到样品有多么薄的是在边缘附近,显现干涉图样,由样品上反射的光和样品边界表面上的光干涉引起的。这告诉我们,样品厚度和光的波长相似,或者在那一点是几倍波长的厚度。样品必须达到这么薄,才能适合TEM工作。

LED TEM sample interference patterns

Interference patterns on the LED      在LED上的干涉花样


We then placed the LED into the TEM and examined it at a much higher magnification than previously possible.

我们将LED放入透射电镜TEM中,使用比先前高很多的放大倍数检测。
LED under TEM

The first image we took under the TEM mainly showed us the dirt that had got onto the sample.

从TEM上获得的第一张图像主要显示给我们样品上面的污染物
LED Moire

When we zoomed in further we saw Moiré fringes appear in the dirt.
       我们进一步放大,我们看到叠栅条纹在污染物中出现。
LED electron defraction pattern

We were able to obtain an electron diffraction pattern which would help us discover what the spacing between the planes of atoms were.  我们可以获得一个电子衍射花样来帮助我们揭示原子晶格空间间距。


Microchip 微芯片

The second component we examined from the mobile phone, is one of the microchips. There were four on the phone's circuit board, and we chose one, and first of all, placed it under the optical microscope and took some photos. Some of these are shown below.
      我们检测的手机第二个元件是一个微芯片。手机电路板中有四个,我们选择一个,首先使用光学显微镜获得一些图像,如下图。

Microchip under optical microscope Microchip under optical microscope

Microchip under optical microscope

These photos show the microchip in more and more detail, having zoomed in further with the optical microscope.
这些图像显示,使用光学显微镜进一步放大,微芯片显示越来越多细节

Chip under the TEM 在透射电镜中的芯片。

We prepared the chip for placing in the TEM the same way as the LED, and a picture of the sample we placed in is shown below, taken with an optical microscope.
      我们使用LED同样的透射电镜样品制备方法,我们放入的样品图像显示如下,光学显微镜拍摄

snap-152552-0007.jpg

We would be examining the region along the top of the sample, to see the transistors.
      我们将检测样品的顶部区域,看这个晶体管。


Below is the first picture we took using the TEM of the transistors on the chip. This was a very low magnefication, only 4000x, and showed the component parts before we zoomed in even further. One can see the different drains and source, along with the gates used to control the current. Different layers can also be seen, where different layers of oxide havae been grown on the silicon chip.
      下面是我们使用TEM观察芯片上的晶体管获得第一张图。这是一张很低的放大倍数,只有4000倍,在我们进一步放大前,显示元件的各部分。你可以看到不同的源和渠,伴随用来控制电流的门。也可以看到不同的层,不同的氧化物层生长在硅片上。

lowmag_1.2kx.jpg
The picture below is taken zoomed in 10000 times. This shows the source for the transistor, with a gate either side.
下面哪的图片是10000倍,显示晶体管的发射源,两边带有门。

gates_4kx.jpg

The picture below is taken, zoomed in 50,000 times. It shows the source on top of the implant, in a silicon layer, surrounded by silicon dioxide. 下面图像5万倍,显示嵌入层顶部的发射源,

drain_10kx.jpg

This picture shows one of the gates, and defects in the silicon near it. These came from the manufacturing process.
下面的图像显示一个门,附近的硅片缺陷。这个来源于制造过程。

gate_15kx.jpg

The picture below shows the gate in greater detail. One can see there is a gap between the Polysilicon gate and the silicon base, which acts as a parallel plate capacitor, which can be used to the manipulate the surrounding electric field. There is a metal cover on top to improve the conductivity of the gate.
       下图显示门更大的细节,在多晶硅门和硅基片之间有一个间隙,作为一个平行板电容器,可以用来操纵周围的电场。
在门的顶部覆盖一层金属提高门的导电性。

gate_40kx.jpg
The final picture we took of the gate was zoomed in 500,000 times. Here we can measure the gap between the gate and silicon to be 19.6nm or around 200 atoms thick. Generally, the smaller the gap, the better the gate can work, but this gate works at a too high voltage, and is also around 10 years behind current standards.
最后图片,放大50万倍,这里我们可以测量间隙尺度是19.6nm,大约200个原子厚度。通常间隙越小,门的作用越好,但门工作在太高的电压,这比当前的标准落后10年。

电子显微技术观察:我的手机里面有什么?LED,Chip,SAW - 驰奔 - --COXEM有限公司 中国代表处--
 
Surface Acoustic Wave Device 表面声波装置

The next device we examined was a Surface Acoustic Wave (SAW) device. This is a device used to pick out a particular frequency of wave, and damp out all the other frequencies, so only the desired frequency, and no other background waves are picked up.  They are used in mobile phones as they are cheaper, smaller and are better than other alterantives such as quartz crystal. 
      我们检测的下一个装置是表面声波装置(SAW)。这个装置用来提取特殊频率的波,渐次减弱其他频率的波,因此只有需要的频率,没有背景波被提取。用在手机上更便宜更小,比其他诸如石英晶体替代物更好。

SAW

The SAW device under an optical microscope. 光学显微镜下的SAW装置

These devices work by mechanical oscillating up and down at the freqency of the desired wave.  At this frequency, it can pick up the wave, but other frequencies get absorbed out of the wave, anso you could get a wave at a desired frequency. Below is a picture of the device taken with an optical microscope from an angle, and it shows different coloured lines of the transducers, which highlights the different spacing between the electrodes, which corresponds to different frequencies of the wave.
      这个装置通过在需要波的频率下上下机械振荡来工作的。在这个频率下,它可以提取波,但其他频率的波得到吸收。下图是使用光学显微镜从一个角度拍摄的图像,显示不同的颜色传感器线,突出电极之间的不同间距,和不同的频率波相符合。

SAW colour

SAW device highlighting different electrode spacings.  突出不同电极间距的SAM装置

The picture below shows buffers at the end of the transducers, which are not connected to the rest of the transducer. These damp out the wave at at the end to stop it continuing.
 下图显示传感器的末端的缓冲器,没有连接在传感器的剩余部分。这用来在末端渐次减弱阻止其继续。


SAW 100x

Zoomed image of the electrodes, with the ones on the right not connected, to damp out the wave.


This lack of connection is hgihlighted in the picture below, which was taken in the SEM, where we can see the buffers on the end charging up because they are not connected to the rest of the device.

下面的图片扫描电镜的图像,突出显示没有连接,我们可以看到在充电末的缓冲器。

SAW charging

The buffers on the right are charging much quicker than the rest of the SAW.
右侧的缓冲器比SAW其余部分更快的而充电

SAW Composition SAW化学成分

Using the X-ray analysis in the SEM, like we did for the LED, we tried to examine what the SAW device was made of. We first looked at the metal around the outside of the device, and then the substrate in the middle, and the results are shown below.
       使用扫描电镜中的X射线能谱,检测SAW装置的化学组成。首先看装置周围的金属,然后是中部的基体,结果显示如下。

SAW metal composition
The graph above is from the X-ray analysis of the metal round the outside, and appears to contain Oxygen, Aluminium, Silicon and Tantalum. However the main peak for silicon shown also contains one of the characteristic peaks for Aluminium. Because of this we were not totally sure whether it contains Silicon or not, but fairly certain about the other 3 elements. We used computer software to generate a graph of what a material under the same conditions would give under X-ray analysis, if it contained Silicon, and then if it did not. This confirmed that Silicon was present, as the peak labeled as Silicon was absent when we generated a graph of the material without silicon, confirming it was not just another Tantulum peak.
能谱图显示含有氧,铝,硅,钽。然而硅的主峰也显示包含一个铝的特征峰。由此,我们不能完全确认是否含有硅,但相当肯定其他三种元素存在。我们使用电脑软件生成一个图,在同一x射线分析条件下将材料是什么的图,到底有没有。确认硅是存在的。使用谱峰核查功能。

SAW substrate

The analysis for the substrate showed very similar results, containing the same peaks as before but the dilemma about Silicon is still present, but our test on the other part of the substrate suggests that it will contain Silicon aswell. Therefore we expect it to have a similar composition to the rest of the SAW device, but in different concentrations.

      基体分析显示相似的结果,包含和前面相同的峰  ,但依然对硅是否存在不能下结论,但在基体的其他部分暗示硅也存在。


英国华威大学的显微镜技术:Microscopy at Warwick
http://www2.warwick.ac.uk/fac/sci/physics/research/condensedmatt/microscopy/

电子显微技术观察:我的手机里面有什么? - 驰奔 - --COXEM有限公司 中国代表处--

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