| 摘要: | 隨著積體電路須具低功率及高性能的要求，銻化物材料系列已被評估具有高潛力適合應用於高速電子元件，其中砷化銦及銻化銦鎵皆擁有III-V族半導體中高載子遷移率等材料特性。在眾多高介電係數材料之中，氧化鋁是一種非常有潛力成為高介電係數材料的候選之一，其本身具有足夠的介電係數、高能隙、高崩潰電場、良好的熱穩定性以及非晶型態的晶體結構。因此，在本論文中我們使用高介電係數材料氧化鋁作為閘極氧化層，成功發展出銻化物金屬-絕緣體-半導體異質接面場效電晶體元件，並且作了深入的分析與探討。 首先針對原子層沉積所成長的氧化鋁薄膜，進行厚度測量和表面粗糙度之物性分析以及利用橢圓儀評估光學特性，並在砷化銦基板上使用不同化學溶液作表面處理，再將其製作成電容器，利用電容-電壓、電流-電壓與崩潰電場量測，研究電容器之電性特性，進而決定最佳的氧化鋁薄膜元件適用條件。最後，將氧化鋁薄膜成長於砷化銦/銻化鋁(InAs/AlSb)和銻化銦鎵/銻化鋁(InGaSb/AlSb)磊晶結構上，製作成電晶體並研究元件的特性。InAs/AlSb n-channel MIS-HFET元件特性上，閘極長度Lg = 2 μm，其汲極飽和電流為IDSS = 371 mA/mm及轉導增益Gm = 604 mS/mm，次臨限斜率為S.S. = 137 mV/dec，電流增益截止頻率fT為10.6 GHz。InGaSb/AlSb p-channel MIS-HFET的元件特性在閘極長度Lg = 1 μm，得到最大汲極飽和電流為31 mA/mm，轉導增益為Gm = 43 mS/mm以及次臨限斜率為S.S. = 153 mV/dec。Since low-power consumption and high performance are required in the integrated circuits, Sb-based materials are considered to be high potential candidates in high speed electronic device applications, due to the InAs and InGaSb showing highest carrier mobility properties among III-V compound semiconductors. Among a number of high-k dielectric materials, Al2O3 become one of the candidates for high dielectric constant materials used for most electronics. The major reasons are that Al2O3 shows a large dielectric constant, a large bandgap, a high breakdown field, a good thermal stability, and amorphous type of crystal structure. Therefore, in this thesis, the high dielectric constant material of Al2O3 had been used as gate dielectric to develope the Sb-based metal-insulator-semiconductor heterojunction field effect transistors (MIS-HFETs) with in-depth analysis and discussion. We first analyzed physical and optical properties of the Al2O3 thin film deposited by atomic layer deposition. The physical properties analysis included film thickness, surface roughness and the optical properties by ellipsometer. The various surface treatments of InAs substrate using different chemical solutions were studied in order to investigate the properties of the InAs MOS capacitors. The electrical property characteristics included C-V, I-V and J-E measurements were characterized to obtain the optimum conditions of Al2O3 film for MIS-HFET application. Finally, we fabricated MIS-HFETs using the Al2O3 deposited by ALD as gate dielectric on the conventional InAs/AlSb and InGaSb/AlSb HFET epitaxy materials. The fabricated InAs/AlSb n-channel MIS-HFET with a gate length of 2 μm, demonstrated the maximum drain current (IDSS) of 371 mA/mm, a transconductance (Gm) of 604 mS/mm, and a subthreshold slope is 137 mV/dec, and a peak current gain cut-off frequency (fT) of 10.6 GHz. The InGaSb/AlSb p-channel MIS-HFET with 1μm gate length showed, the maximum drain current of 31 mA/mm, transconductance of 43 mS/mm, and the subthreshold slope of 153 mV/dec. |
