應用於無線電通訊之低操作電壓砷化鎵功率金屬半導體場效電晶體之研究

Abstract

在無線通訊上，對於低電壓使用的功率模組需求，日益增加；且必須能同時滿足高輸出及高效益的特性。因此，我們以縮短汲極和源極間距，及縮小元件整體尺寸來改進元件的特性，以滿足低操作電壓之需要。 我們克服了因為元件縮小，所造成製程上的困難；並且找出了適當的製程條件以完成元件。經由此製程製作的元件，我們得到很好的元件特性。閘極寬3.36mm 的元件，在2.4GHz，2伏偏壓的量測條件下，其在PldB的功率增益可達44%。閘極寬6.72mm的元件，在2.4GHz，3.5伏和4.7伏偏壓的量測條件下，其在PldB的功率增益分別為47%和50%。至於閘極寬20.16mm的元件，在2.4Hz，3.5伏和4.7伏偏壓的量測條件下，其最大的功率輸出分別約為1.5瓦特和2.5瓦特。 總之，我們在縮小元件尺寸的前提下，做出了不同閘極寬度的元件，同時實現了大閘極寬度元件的製程（20mm），這些元件有極佳的元件特性。在低電壓操作時，符合大哥大通訊的一些規格要求。因此，我們可從結果看出，此元件在下一代的無線通訊應用上具有很大的潛力。

There is an increasing demand for power amplifiers that can be operated at low bias voltage cellular communication systems. Simutaneously achieving high power and high efficiency poerformance is strongly required for the low bias voltage operated cellular communication applications. Therefore, we developed the devices in an improved structure with reduced drain to source spacing and in a shirinkage device pattern to achieve this goal. We have optimized the process conditions and overcome the difficulties of the process due to the shrinkage of the device pattern. The power performance of the device pattern. The power performance of the devices developed is notable. The 3.36mm-wide device achieves 44% power-added efficiency at the 1-dB gain compression point under 2V bias conditon and at 2.4GHz. The 6.72mm-wide device achieves 47% and 50% power-added efficiency at thel-dB gain compression point under 3.5V and 4.7V bias condition and at 2.4GHz. The 20.16mm-wide device delivers a maximum output power of about 1.5W and 2.5W under 3.5V and 4.7V bias condition. At last, we demonstrate the high outoput power with long gate width in a shrinkage device pattern, and the notable pow-added efficiency of the 3.36mm-wide device under low operation voltage. In this way, the result shows that the device is very useful for the next generation wireless communication applications.