砷化鎵850nm面射型雷射之製程技術與特性研究

Abstract

本論文主要在探討砷化鎵面射型雷射之製程技術與特性研究，其中包括氫離子佈植850 nm 面射型雷射的製程技術研究、元件尺寸對特性的影響以及佈植能量對電流侷限的影響。我們已建立氫離子佈植電流侷限面射型雷射之製程技術，包括曝光條件、顯影時間、電極材料、氫離子佈植能量，並成功地製作出面射型雷射。在探討雷射特性方面，我們針對氫離子佈植能量為200keV，佈植劑量為1×1015 cm-2所製作之雷射作不同尺寸的金屬接觸以及出光孔徑大小變化，探討其對雷射電阻和臨界電流的影響，我們發現在相同的金屬接觸尺寸下，孔徑愈小的雷射有愈大的電阻及愈小的臨界電流。其中金屬接觸為300×300µm2，孔徑為8µm的雷射有最小的臨界電流5.5mA，電阻為42.2Ω。至於金屬接觸的尺寸對電阻的影響並不是很大，以孔徑為10µm為例，金屬接觸尺寸從200×200到500×500µm2，電阻在35〜36Ω之間。 我們並探討佈植能量對電流侷限的影響，在相同佈植劑量1×1015 cm-2下，改變四種佈植能量200、250、300、350keV。我們發現佈植能量為250keV時，孔徑為10µm，金屬接觸尺寸為300×300µm2的雷射有最低的臨界電流2.7mA和最高的光強度輸出2.38mW。

The thesis mainly focuses on the study of fabrication techniques and characterization of GaAs VCSELs; the content includes the study of fabrication techniques of 850 nm proton implanted VCSELs, the influence of laser dimensions on characteristics, and the influence of implantation energy on current confinement. We had established the fabrication techniques of current-confined proton implanted VCSELs including exposure condition, development time, metal contact, and proton implantation energy; as a result, a lot of VCSELs were successfully fabricated. In discussing laser characteristics, the dependence of resistance and threshold current on dimensions of contact pad and aperture was studied. We found that for a given contact pad size, with a dose of 1×1015 cm-2 200 keV protons, smaller aperture led to higher resistance and lower threshold current. With a 300×300 µm2 contact pad and an 8 µm aperture, the VCSEL achieved the lowest threshold current of 5.5 mA and the resistance was 42.2 Ω. However the pad size didn’t influence the resistance severely. In the case of 10 µm aperture, the contact pad size from 200×200 to 500×500 µm2 led to the resistance from 35 to 36 Ω. With a dose of 1×1015 cm-2 protons, four kinds of energy of 200, 250, 300, and 350 keV were employed to study the dependence of current confinement on implantation energy. We found that for the VCSEL with a 10 µm aperture and a 300×300 µm2, the implantation energy of 250 keV gave rise to the lowest threshold current of 2.7 mA and the maximum output power of 2.38 mW.