- 學位論文
(110)晶圓面上矽鍺源汲極MOSFET的載子遷移率
Carrier Mobility for MOSFET Using SiGe-Source/Drain on (110) Wafer Surface
摘要
在多種應變矽的方法中，以矽鍺源汲極(SiGe-S/D)為相當可行的技術之ㄧ，但是應用在(110)晶圓面上，其特性與機制尚未十分地清楚。此外在近五年來，漸漸也有作者在研究由溫度效應對應變MOSFET產生的影響，且探討到散射(scattering)機制的問題，但針對SiGe-S/D因溫度而產生的效應，文獻探討的並不多。 所以本研究使用(110)的晶圓面，對具SiGe-S/D與矽源汲極(Si-S/D)的MOSFET以及未受應變的MOSFET，就通道長度的不同，探討溫度對其載子遷移率的影響。實驗的測試以25 o C與125 o C兩種溫度進行。在測試中，分別在兩種溫度下測量出不同通道長度之MOSFET的驅動電流以及計算出載子的遷移率。在完成實驗後，進行結果與討論。結果發現，在MOSFET上，三種元件皆受到溫度升高而導致載子遷移率劣化，是因為受到聲子散射 (phonon scattering) 所影響。此外，將結果由公式計算得知，長通道比短通道較易受溫度的影響，除了聲子散射之外，最主要是因為通道較長，載子與晶格互相撞擊的機會較多，導致載子遷移率減少量比短通道來得多。另一方面，無論通道長短，n-MOSFET之拉應變與p-MOSFET之壓應變愈大者，其溫度的影響效應愈大。
並列摘要
In many strained methods, the process of SiGe-S/D has been worth applying. Nevertheless, the mechanism and characteristic were not so clear by applying on (110) wafer surfaces. For past five years, some studies of the temperature dependence on MOSFET devices have been investigated. Moreover, the scattering mechanism has been investigated to the strained MOSFETs. However, the SiGe-S/D with temperature dependence of channel lengths were less mentioned in the previous references. Therefore, it would use the devices of SiGe-S/D, Si-S/D, and control to discuss the carrier mobility on the temperature dependence. The temperatures are 25 o C and 125 o C. In the experiment, the drive current and mobility are created with different lengths at two temperatures. The results indicates that the carrier mobility is degraded by the temperature increasing. The phonon scattering is an important factor. Moreover, the long channel of the temperature effect is higher than the short channel. The factor is not only the effect of phonon scattering but also the probability of the impact to the lattice is higher than the short channel. On the other hand, the tensile strain of n-MOSFET or the compressive strain of p-MOSFET makes the temperature dependence increases gradually.