1奈米等效厚度之氧化鑭與氧化鉿複合氧化物材料在砷化銦鎵金氧半元件之研究

Abstract

在本研究中,氧化鑭及二氧化鉿作為金氧半電容的閘極氧化層在砷化銦鎵基板上.鉿系鑭系為主體做為閘極氧化層有很多優點,像是具有高介電係數,寬能隙以及較高的結晶溫度.這些結果說明了,在互補式金氧半場效電晶體中的應用中,鉿系鑭系氧化物系統成為有潛力的選項. 複合式氧化物是利用分子束沉積4層的1奈米二氧化鉿疊上1奈米氧化鑭,以及8層的0.5奈米二氧化鉿疊上0.5奈米氧化鑭,且經過不同快速熱退火溫度.我們藉由XPS、TEM、EDX分析以及C-V量測得到此種複合氧化物的特性.這種疊層結構的設計,不但可以提升電容值同時減緩氧化物及半導體的擴散現象.最後,由二氧化鉿疊上氧化鑭在砷化銦鎵基板上製成的金氧半電容器,我們呈現了電容等效厚度達到1.2奈米,磁滯現象的電壓變化量為78× 10-3伏特,且得到不錯的介面特性.

In this study, La2O3 and HfO2 were used as gate oxides on InGaAs metal oxide semiconductor (MOS) capacitor. There are many advantages of Hafnium–Lanthanum-Based gate dielectrics, such as high dielectric constant, large energy bandgap and high crystallization temperature, etc. These results suggest that the (Hf–La)Ox system will become a potential candidate for advanced CMOS applications The composite oxide was formed by MBD depositing 4 layers of La2O3 (1nm)/ HfO2(1nm) and 8 layers of La2O3 (0.5nm)/ HfO2(0.5nm) on InGaAs with varied post deposition annealing (PDA) temperatures. We have the characterized properties of the La2O3/ HfO2 on InGaAs MOS structure by using XPS, TEM, EDX and C-V measurement. The design of the stack structure can improve the capacitance meanwhile prevent the diffusion between the oxide and the semiconductor. Finally, we have demonstrated the 1.2-nm-thick capacitance equivalent thickness in the La2O3/HfO2/n-InGaAs MOS capacitors with good interface properties and small hysteresis of 78mV.