本研究主要是專注於波長為248奈米的KrF準分子脈衝雷射與氮化鎵磊晶薄膜間交互作用的探討。其中從先前的文獻研究中已指出在準分子雷射剝蝕氮化鎵的過程中，會伴隨著反應產物－「鎵」的生成。然而，當利用不同雷射能量密度輻照至氮化鎵薄膜表面後，可以發現其表面形貌的呈現有非常大的差異。在低雷射能量密度時，氮化鎵可形成一密集且粗糙的表面；在高雷射能量密度時則為一極平坦的連續表面。造成此一現象的主要因素很可能是反應產物「鎵」在不同雷射能量下以不同的形式殘留在氮化鎵表面的結果。因此，反應產物對於雷射剝蝕氮化鎵之中扮演著什麼樣的腳色與形成的原因都將會在此做進一步的討論與分析。再者，我們還將呈現在不同環境溫度下，準分子雷射對氮化鎵剝蝕速率的影響並討論其行為。 We represent an irradiation study on III-V GaN compound by pulsed KrF excimer laser with the wavelength at 248 . As we know, GaN will be decomposed to Gallium metallic droplets during laser ablation. How does the reaction products (i.e. Ga droplets) affect the laser ablation on GaN is an interesting issue to study. In this work, two different kinds of laser irradiation conditions were conducted: (1) continuous laser irradiation. (2) non-continuous laser irradiation. In this condition the effect of laser reaction products on the laser ablation process was isolated by removing Gallium metallic droplets after each laser irradiation pulse. From the results of the continuous laser irradiation, we found that the etched depth increases linearly with the numbers of pulses, and the laser etching rate increases with the laser fluence. However, the relation between the etching rate and laser fluence appears nonlinearly. At higher laser fluence, the etching rate is smaller. Also, we found that the laser absorption ability decreases with increasing pulse numbers at constant laser fluence. For non-continuous laser irradiation, we can observe that the ablation rate is higher than that of the case of the continuous irradiation. Detail mechanism and experimental results will be reported in this talk.
