雷射退火在氧化物半導體及導體上之應用研究

Abstract

氧化銦鎵鋅薄膜電晶體具有在非晶態下，仍能保有高載子移動率，且能於低溫成長；另外，氧化物半導體在可見光區下大多為透明，可用於提升平面顯示器之開口率。顯示出氧化物半導體具有高度取代非晶矽和低溫多晶矽的潛力。 雷射製程常被利用於加熱非晶矽使成長為多晶矽去製作低溫多晶矽薄膜電晶體。在本論文中，我們研究雷射退火製程對氧化銦鎵鋅薄膜包含物理和化學方面的影響，以及利用TLM的結構研究雷射退火製程對金屬-半導體接觸電阻的影響。 藉著控制適當的雷射製程條件，氧化銦鎵鋅薄膜的電阻率可以下降至6.8×10-3 Ω-cm，和金屬電極的接觸電阻率下降至6.5×10-5 Ω-cm２，接著我們提出利用雷射製程降低串聯阻抗和接觸電阻去製作上閘極self-aligned氧化銦鎵鋅薄膜電晶體的方法，相較於傳統熱退火方式，雷射製程對於基板的的熱效應可大幅減少，有機會實現在塑膠基板上製作高效能氧化銦鎵鋅薄膜電晶體。

Oxide thin-film transistors could exhibit high mobility even in the amorphous phase and could be fabricated at low temperature. In addition, their transparency in visible region can improve the pixel aperture ratio in flat-panel displays. These benefits of oxide TFTs render their highly potential to replace amorphous silicon (a-Si) and low-temperature ploy Si (LTPS) TFTs. The laser processing is commonly used in the fabrication of LTPS TFTs, to crystallize a-Si film. In this thesis, we studied the effects of laser processing on physical and chemical properties IGZO thin films. We also studied the metal-semiconductor contact resistances of laser process of IGZO. By proper laser processing conditions, the resistivity and specific contact resistivity down to 6.8×10-3 Ω-cm and 6.5×10-5 Ω-cm２, respectively, could be achieved with IGZO. With these, we proposed a method to fabricate top-gate self-aligned IGZO TFTs utilizing laser processing. This method is promising for achieving high performance IGZO TFTs on plastic substrates because the thermal damage to substrates might be reduced compared to conventional furnace annealing.