论文标题
在侧面植入的4H-SIC MOSFET中沉积的SiO2层的界面电和化学性质，受到不同的硝化作用
Interfacial electrical and chemical properties of deposited SiO2 layers in lateral implanted 4H-SiC MOSFETs subjected to different nitridations
论文作者
论文摘要
在本文中，研究了沉积在4H-SIC上的SIO2层，并研究了NO和N2O中的不同后沉积退火（PDA），以识别影响4H-SIC MOSFET的通道迁移率和阈值电压稳定性的关键因素。特别是，NO中的PDA比N2O中的PDA更高（55 cm2v-1s-1）（20 cm2v-1s-1），并且设备的亚阈值行为证实了NO情况的界面总数较低。后者也可以从在门控制的二极管配置中测得的4H-SIC MOSFET的电容 - 电压特性的行为推导。另一方面，循环栅极偏置应力测量值可以将4H-SIC带隙上和底部的界面状态（NIT）的贡献分开，并将两个氧化物中的界面氧化物陷阱（NIOTS）分开。特别是发现，没有退火降低了被困在界面状态的电荷的总密度降低至3 x 1011 cm-2，而被困在氧化物内部的电荷一直降低至1 x 1011 cm-2。电子能量损失光谱表明，在NO退火样品中这些陷阱的减少是由于氧化硅（〜1NM）的量较低，并且分别在界面处的碳相关缺陷（<1nm）。这种相关性代表了理解SIO2/4H-SIC界面物理学的进一步步骤，该界面解释了4H-SIC MOSFET的迁移率和阈值电压行为。
In this paper, SiO2 layers deposited on 4H-SiC and subjected to different post deposition annealing (PDA) in NO and N2O were studied to identify the key factors influencing the channel mobility and threshold voltage stability in 4H-SiC MOSFETs. In particular, PDA in NO gave a higher channel mobility (55 cm2V-1s-1) than PDA in N2O (20 cm2V-1s-1), and the subthreshold behavior of the devices confirmed a lower total amount of interface states for the NO case. This latter could be also deduced from the behavior of the capacitance-voltage characteristics of 4H-SiC MOSFETs measured in gate controlled diode configuration. On the other hand, cyclic gate bias stress measurements allowed to separate the contributions of interface states (Nit) both on the upper and bottom parts of the 4H-SiC band gap and near interface oxide traps (NIOTs) in the two oxides. In particular, it was found that NO annealing reduced the total density of charges trapped at the interface states down to 3 x 1011 cm- 2 and those trapped inside the oxide down to 1 x 1011 cm-2. Electron energy loss spectroscopy demonstrated that the reduction of these traps in the NO annealed sample is due to the lower amounts of sub-stoichiometric silicon oxide (~ 1nm) and carbon-related defects (< 1nm) at the interface, respectively. This correlation represents a further step in the comprehension of the physics of the SiO2/4H-SiC interface explaining the mobility and threshold voltage behavior of 4H-SiC MOSFETs.
