分子束磊晶成長矽摻雜氮化鎵薄膜之特性分析

Growth and characterization of Si doped GaN thin film grown by Molecular Beam Epitaxy

郭季安(Ji-An Guo)

指導教授 ： 周武清

國立交通大學/理學院/電子物理系所/碩士(2019年)

摘要

本論文使用分子束磊晶成長矽摻雜氮化鎵薄膜。研究改變不同長晶參數對薄膜的表面形貌的影響。再利用控制不同矽材料源溫度，以改變矽原子的摻雜濃度，並對其電特性、光學特性以及表面形貌作分析。
　　在矽摻雜氮化鎵薄膜研究中，以矽材料源溫度為1140℃時具有最平滑的表面形貌。而在溫度1150℃時有最高的矽原子摻雜濃度，此時表面出現矽金屬的析出，因此得知其為由分子束磊晶成長此結構的摻雜極限。此外，我們可以觀察到光激螢光譜譜峰一開始呈現隨著矽參雜濃度增加而紅移的現象，此現象歸諸因矽參雜而引起的晶格壓縮應變。當矽參雜濃度增加到臨界濃度1019cm-3時，光激螢光譜譜峰開始出現藍移現象，此現象歸因於過多的參雜使得電子填到導電帶以上。

關鍵字

分子束磊晶 ； 矽摻雜氮化鎵 ； 三五族

並列摘要

In this thesis, Si doped GaN thin films were grown by molecular beam
epitaxy (MBE). The effect of growth parameters on the surface
morphology was studied. The Si doping concentration was controlled by
varying the efficient cell temperature of Si. Effect of the Si doping
concentration on the electrical properties, optical properties and surface
morphology were investigated.
For the Si doped GaN thin films, the best surface morphology is
obtained when the silicon cell temperature is 1140 °C. The highest
doping concentration is achieved at the cell temperature of 1150 °C.
However, precipitation of silicon on the sample surface was observed. It
could be the solubility limit of Si dopants in GaN of this structure grown
by MBE. In addition, in the optical measurement, we can observe the
existence of a critical doping concentration 1019cm-3. The photoluminescence (PL) peak energy initially red-shifts with the increasing doping concentration and then blue-shifts when the doping concentration reaches the critical value. The initial redshift could be attributed to the increasing compressive strain with Si doping. The following blue-shift as the doping concentration exceeding 1019cm-3 could be due to the band filling effect.

並列關鍵字

MBE ； Si doped GaN

參考文獻

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