| 摘要: | 摘 要 隨著個人無線通訊系統熱烈蓬勃的發展，微波射頻電路模組的效能及品質往往決定無線通訊晶片模組的競爭力，也因此通訊品質的好壞與可傳送的資料量大小皆成為重要的關鍵。但在頻寬有限的情況下，無線通訊勢必朝向更高頻與微波領域發展，以提供更卓越的通訊品質。在射頻電路模組中，功率放大器之效能決定了整體射頻模組的大部分功率損耗，所以其品質好壞與否往往主宰了電池的續航力。故本論文主體從主動元件之設計，開發，與改良，配合新型材料之被動元件，橋墩立體技術設計並研製出一C-頻段(5.8 GHz) 單晶微波功率放大器及一K-頻段(20 GHz) 增益放大器。 在本論文中，延續著本實驗室在通道摻雜異質接面場效應電晶體高電流推動能力，高線性度，以及高崩潰電壓之研究，首先我們利用不同的磊晶結構改善電晶體之高源極和汲極阻抗，再配合不同之製程技術改良元件之閘極漏電流，進而改善整體元件功率特性及效能。 在第三章中，由於功率元件在操作時極易產生出大量的熱，而此因素又會影響元件之特性，所以此章節針對通道摻雜異質接面場效應電晶體以及傳統高電子移導率電晶體 (HEMTs) 進行一系列元件直流，高頻，以及功率方面高溫特性之研究。 第四章的部份主要是應用低介電係數材料(BCB)製作主動元件之覆蓋層以及功率元件之橋墩技術，相較於傳統製程此先進材料既不會增加太多的寄生電容，也可大幅度簡化製程之步驟。 在第五章中，為了大幅度增加元件之有效操作頻率，我們利用電子束微影設備及三層電子束光阻開發出閘極寬度為0.2微米之T-型閘極，此先進製程將元件電流增益截止頻率及功率增益截止頻率大幅增加為45 GHz 以及 90 GHz。除此之外，也利用改良式Curtice大訊號模型建立此主動元件之模型，並配合負載拉引功率量測系統驗證此大訊號模型。 最後，利用高頻電路設計軟體，電磁場論模擬被動元件之特性，並配合光罩製版，金屬剝離，以及電子束微影技術完成適用於C-頻段以及 K-頻段單晶微波積體功率放大器。 ABSTRACT Deep sub-micron doped-channel heterostructure field-effect transistors (DCFETs) with a high current density and superior microwave power performance was developed and characterized. Due to its excellent current driving capability, Schottky gate performance and thermal stability, it has been widely investigated for microwave power devices and high-speed devices. A major drawback of DCFETs is their large parasitic source and drain resistances caused by using a high bandgap undoped Schottky layer beneath the gate metal. In this regard, we proposed a method to reduce parasitic resistances by inserting a planar Si δ- doped layer into the InGaP Schottky layer to solve this problem. Furthermore, to achieve a high yield and high uniformity of large area power device crossing the wafer, reactive ion etching was applied to the gate recess process of InGaP/InGaAs doped-channel heterostructure FETs. Power transistor consumes a lot of dc power and a huge amount of heat will be generated during the operation, this affects the performance and the reliability of devices and circuits. To ensure a stable high power performance of a FET for long-time operation, its evaluation at high temperatures is an essential issue, since large amounts of heat will be generated during the operation. In this study, we will discuss the effect on the dc, rf, and power characteristics between DCFETs and pHEMTs from room temperature (25 C) to 150 C. A novel Al0.5Ga0.5As/InGaAs enhancement mode pHEMT with a large linear operation range was developed and studied. In order to achieve an enhancement-mode operation in pHEMT design, the thickness of the device Schottky layer is more flimsy than the traditional depletion-mode design. This thin Schottky layer results in the device performance being easily influenced by the surface states, owing to the channel layer closing to the surface. Therefore, we apply the low-k photo- sensitive-benzocyclobutene (BCB) layer to replace the traditional SiNx passivation layer. In addition, BCB passivated layers also reduce the oxidization problem in a high Al mole fraction Schottky layer. In order to fabricate high performance microwave power transistor for millimeter wave application, sub-micron T-shape gate demonstrated by using e-beam lithography is an efficient method. By using Raith-150 e-beam writer and tri-layer polymer photoresist, the 0.2 µm gate length InGaP/InGaAs DCFET was developed and characterized. Besides, the Curtice large signal model was applied on 0.2 µm gate -length InGaP/InGaAs DCFET. In order to quality the accuracy of the established Curtice model, the device load-pull results which is including power performance, load impendence, are compared with the simulated results on HP advanced design system (HP-ADS) environment. C-band and K-band MMIC amplifiers based on 0.2 µm gate length InGaP/InGaAs DCFET and BCB passive components have been designed and fabricated. The BCB 3-D MMIC exhibits several benefits including simple process, low parasitic effects for active device, and high circuit robustness. Based on the well-predicted active and passive components, these C-band and K-band MMIC amplifiers were fabricated in our lab. |
