使用閘極介電質成長後電漿處理法改善三五族砷化銦鎵鰭式場效電晶體元件特性之研究

Abstract

在這項研究中，我們製造了砷化銦鎵(InGaAs)的鰭式場效電晶體(FinFET)和全包覆式閘極場效電晶體(GAA-FET)，利用閘極介電質成長後電漿處理法(in situ post remote-plasma treatment)來提升此元件的特性。我們使用精準的乾蝕刻和濕蝕刻技術來製造非平面式的元件，我們可以蝕刻出最小的鰭式寬度為50奈米和通道長度為80奈米的元件。使用遠程電漿處理法，鰭式電晶體體可以改善次臨界擺幅(SS)、汲極感應位障降低(DIBL)、臨界電壓下降(VTH roll-off)還有閘極介電層的品質，使元件的開關特性比達到5個數量級。從我們元件的微縮指標(scaling metric)來看，顯示出在我們製程中，鰭式場效電晶體有優秀抑制短通道效應的能力。 此外，我們還對鰭式場效電晶體做了可靠度的量測，我們藉由正偏壓溫度不穩定性(PBTI)方法來分析元件，我們發現有經過電漿處理法的元件，在高溫高壓有較小的衰退速度，顯示出有較好的可靠度特性，藉由使用原子層化學氣相沉積系統製程，可以以較低溫的環境成長閘極介電質，此方法可以提升氧化層內的鍵結能量和減少陷阱密度(density of trap)，藉由PBTI分析，我們有經過電漿處法的元件在85°C下操作十年，臨界電壓下降30mV，元件的驅動電壓接近0.32V。

In this study, we fabricate In0.53Ga0.47As FinFETs, GAA-FETs and demonstrate on effects of in situ post remote-plasma (PRP) gas treatment on the device performances. Performing dry and wet etching methods, 3D MOSFET devices, owning LCH down to 80 nm and WFin down to 50 nm, have been fabricated and characterized. In situ post remote-plasma gas treatment provides much better electrostatic control and shows improved S.S., DIBL and VT roll-off. Optimizing oxide and interfacial qualities by PRP treatment, a high ION/IOFF of ~ 105 along with better electrical characteristics have been obtained for In0.53Ga0.47As FinFET and GAA-FET devices. Scaling metrics for InGaAs FinFETs are also systematically studied with LCH from 200 nm down to 80 nm and WFin from 90 nm down to 50 nm which shows an excellent immunity to short channel effects. In addition, to evaluate the impacts of in situ post remote-plasma gas treatment on the reliability properties of III-V based 3D MOSFETs, the positive bias temperature instability (PBTI) has also been carried out. The In0.53Ga0.47As FinFET treated by PRP treatment illustrates better reliability performance and less degradation for a long-term stress at large bias voltage and high operate temperature. This can be attributed to stronger bonding energy and lower density of trap states in the high-k gate dielectric. The PBTI results also show that, for an operation lifetime of 10 years at 85 °C, the In0.53Ga0.47As FinFETs achieved in this study with PRP treatment would be ensured to operate at an overdrive voltage of ~ 0.32 V.