有序-無序型磷化銦鎵材料對異質接面雙載子電晶體元件特性之影響

Abstract

本論文之實驗目的在於研究以低壓金屬有機化學氣相磊晶法成長之磷化銦鎵的有序化係數和不同成長溫度之間的關係，最後將應用在異質接面雙載子電晶體上，討論有序化係數對元件特性可能產生之影響。 在實驗中，以光激發儀（PL）探討材料能隙 和長晶溫度之關係，並藉由改變量測輸入功率的方法，最後可以計算出不同長晶溫度磷化銦鎵的有序化係數。雙晶X光繞射法（DCXRD）和拉曼光譜（Raman spectra）亦提供相關的證據解釋了不同有序化係數對磷化銦鎵材料所產生的影響。 為了探討磷化銦鎵有序化係數對元件可能產生之影響，在實驗中製作了雙載子電晶體（HBT）。大顆元件的射極尺寸為100x100平方微米，補償電壓（offset voltage）小於150meV，起始電壓（threshold voltage）為0.75V，在集極電流為137mA時，最大電流增益約為85。根據Gummel plot，集極和基極的電流理想係數分別約為1.05和1.35。小顆元件尺寸為4x20平方微米，補償電壓和起始電壓與大顆元件類似，最大電流增益約為95，極集和基極電流理想係數為1.05和1.75。 以650oC成長之磷化銦鎵為射極的HBTs，最大電流增益約為65，而以610oC成長的HBTs最大電流增益為85，這顯示出無序化結構磷化銦鎵能隙較有序化結構為大而使得無序化結構有較佳的操作性能，這也與理論和分析結果符合。

In this thesis, lattice-matched In0.49Ga0.51P alloys grown by Low Pressure Metalorganic Vapor Phase Epitaxy (LP-MOVPE) were studied by photoluminescence spectra, double crystal x-ray rocking curve diffraction analysis and Raman scattering spectra. This emphasis of the study focused on the analysis of InGaP CuPt type spontaneous ordering. The results reveal that the ordered structure exists in the growth temperature range from 610 to 680oC. The highest order parameter of InGaP exists in the grown temperature at 650oC. The InGaP/GaAs HBTs process is established to investigate the effect of InGaP order parameter on HBTs performance. The DC characteristics of the HBT devices were measured. The offset voltage is smaller than 150 meV and the threshold voltage is about 0.75V. The ideally factors for collector and base current are about 1.05 and 1.35, respectively. The current gain of InGaP sample grown at 650oC is about 65 at IC=87 mA, and the current gain of InGaP sample grown at 610oC is about 85 at IC=145 mA. It shows that the disordered InGaP emitter provides higher current gain than the ordered one due to higher energy band gap which is in consistent with the theoretical prediction.