臺灣博碩士論文加值系統

在本篇論文中,我們將介紹金屬-半導體-金屬光檢測器的製造與特性.首先
在第二章中,我們要先設計金屬-半導體-金屬光檢測器的結構.其中要考慮
的因素有二個,一個是RC時間常數及另一個為穿透時間.我們希望能設計反
應速度主要被穿透時間限制的光檢測器.在設計完畢光檢測器後,我們利用
光微影技術來作出元件.接著利用超音波焊接方法,把元件與外部接線.然
後,我們便可以用我們搭設的光學系統來量測金屬-半導體-金屬光檢測器
的特性.一開始,我們要先搭設一個測量直流特性的光學系統來測量靈敏
度(respon -sivity)及量子效率.當入射雷射光的波長為842nm,我們得到
靈敏度值為 0.15. 接著,我們想要搭設一個快速光學量測系統.但是因為
我們的雷射二極體的操作頻率,無法達到15 GHz.所以我們搭設了一個交流
訊號光學量測系統.由此系統我們知道我們的金屬-半導體-金屬光檢測器
可以量測到990 MHz的光訊號. 但是與我們理想的值仍有頗大差距. 所以
我們改用另一種方法來分析.最後,我們使用射頻阻抗分析儀來量測封裝後
金屬-半導體-金屬光檢測器的等效電容與等效電感. 從等效電路圖,我們
可以得到光檢測器的3dB頻率為 2.41 GHz. 而由電路圖,我們知道限制金
屬-半導體-金屬光檢測器的頻率響應的主要因素是電感.而過大的電感值,
乃是由於過長的接線所造成. 所以假如我們要得到較高的3dB頻率, 我們
要先縮短接線的長度.若我們能得到一個15 GHz的光檢測器,我們便可以搭
設一個高速光學量測系統.

In the thesis, we introduce the fabrication and
characterization of the metal-semiconductor-metal(MSM)
photodetector(PD). In the chapter 2,we discuss the RC time
constant and the transit time when we want to design the MSM
PD. We want to get a transit-time-limited device. After
designed the MSM PD, the device was fabricated by the
photolithography.Then the device was bonded by the ultrasonic
method.Therefore, we can measure the characterization of the
MSM PD in the optical system. First, we set up the DC optical
measurement system to measure the responsivity and the quantum
efficiency. The responsivity is 0.15 when the wavelength of the
laser diode is 842 nm. Second, we want to set up the high-speed
optical measurement system. But we don't have a laser diode
that can be operated higher than 15 GHz. So we set up the AC
measurement system to measure the AC signal. The signal whose
frequency is 990 MHz could be detected by the MSM PD. Finally
we use the RF impedance analyzer to measure the equivalent
capacitance and the equivalent resistance. From the equivalent
circuit, we get the f3dB of the MSM PD is 2.41 GHz. The
limitation of the frequency response of the MSM PD is the
inductance that causes by the long bonding wire. If we want to
get the larger value of the 3dB frequency, we must decrease the
length of the bonding wire.