請用此 Handle URI 來引用此文件:
http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/70872
標題: | 短波長紅外線偵測器之砷磷化銦變晶緩衝層應力鬆弛特性 Strain Relaxation Properties of InAsyP1-y Metamorphic Buffer Layers for SWIR Photodetector |
作者: | Hao-Kai Hsieh 謝皓凱 |
指導教授: | 林浩雄(Hao-Hsiung Lin) |
關鍵字: | 短波長紅外線,偵測器,變晶緩衝層,砷化銦鎵,磷砷化銦, SWIR,photodetector,metamorphic buffer layer,InGaAs,InAsP, |
出版年 : | 2018 |
學位: | 碩士 |
摘要: | 本論文開發在n+InP基板之上的InAsP變晶技術,用以成長不具應變的InAsP/InGaAs PIN二極體之SWIR波段偵測器磊晶結構,並以倒置空間圖譜(RSM)、穿透式電子顯微鏡(TEM)、原子力顯微鏡(AFM)驗證變晶層結構。進行完鋅擴散製程之後,量測偵測器的暗電流以及光激發螢光頻譜(PL)來觀察磊晶結構之光電特性。將入射X-ray 沿著[110]和[11 ̅0]兩個方向進行RSM量測,從結果來看,在InAsyP1-y多層的階梯漸變式的緩衝層結構中,推斷磊晶層之應變鬆弛不僅是由上下單層之間的不匹配程度決定,還會受到上方堆疊的磊晶層影響,並且發現磊晶層在晶格鬆弛的過程中,因為在晶格在[110]方向與[11 ̅0]方向有不等量的錯配差排(misfit dislocation) 產生導致不等量的鬆弛現象,此結果會使晶格產生剪應變。
利用TEM技術,來觀察元件的(110)和(11 ̅0)截面圖,我們發現此結構能夠將錯配差排(misfit dislocation)限制在鬆弛層,並且在光吸收層InGaAs中未觀察到穿透(threading dislocation),並且藉由AFM分析來觀察表面形貌的交叉線(crosshatch)。 此外我們進行室溫 300K的光激發螢光頻譜,量測光吸收層InGaAs之能隙 ,並且將應變造成能隙的變化考慮進去,回推InGaAs合金的彎曲參數(bowing parameter) C,以及將鋅擴散製程完之元件進行I-V量測,並利用理論的電流公式進行擬合。 In this paper, we propose to design and grow a metamorphic step-graded InAsP buffer layer on n+ InP substrate to gradually enlarge the lattice constant so as to allow the InGaAs detectors to be grown strain-freely on top of the buffer layers. Reciprocal space mapping (RSM), transmission electron microscopy (TEM) as well as atomic force microscopy (AFM) are used to verify the validity of the design. Diode detectors are fabricated and their photoluminescence (PL) as well as dark current density are measured to verify the quality of the epi-structures. The incident X-ray is measured by RSM in both [110] and [11 ̅0] directions. From the results, in the metamorphic step-graded InAsP buffer layer, it is inferred that the strain relaxation is determined not only by the mismatch between the upper and lower single layers, but also by the epitaxial layer stacked above. We find that lattice shape in [110] and [11 ̅0] direction are different. We attribute the difference to the unequal misfit dislocations generated at these two direction where the lattice is relaxed and the phenomenon results in shear strain. We use TEM technique to observe the (110) and (11 ̅0) cross-sectional images, which show that misfit dislocations are confined in the buffers and no threading dislocations are observed in the absorbing layer and use AFM technique to observe the crosshatch of the surface topography. In addition, we perform a photoluminescence experiment at room temperature of 300K, measure the energy gap of the absorption layer InGaAs, and take into account the variation of the strain causing the change of energy gap to calculate the bowing parameter C of the InGaAs alloy. I-V measurements is taken and fits by using theoretical current equations. |
URI: | http://tdr.lib.ntu.edu.tw/jspui/handle/123456789/70872 |
DOI: | 10.6342/NTU201802455 |
全文授權: | 有償授權 |
顯示於系所單位: | 電子工程學研究所 |
文件中的檔案:
檔案 | 大小 | 格式 | |
---|---|---|---|
ntu-107-1.pdf 目前未授權公開取用 | 3.47 MB | Adobe PDF |
系統中的文件,除了特別指名其著作權條款之外,均受到著作權保護,並且保留所有的權利。