Electrical Properties of HfO2 on Si1-XGeX Substrates Pretreated Using a Y Precursor with and without Subsequent Oxidant Pulsing

We introduced Y-O bonds in the interfacial layer between HfO2 and Si1-xGex (x = 0, 0.15, and 0.3) using two different pretreatment methods to minimize the number of interfacial defects. The pretreatments involved the application of cyclic pulses of Y(CpBut)3 and N2, which proceeded with or without the injection of an oxidizing agent (H2O) at 250 degrees C, which was the temperature used for the subsequent in situ atomic layer deposition of HfO2. Both Y pretreatments were beneficial in reducing the leakage current and positive flatband voltage shift, which were induced by an increase in the Ge concentration of the substrate. In addition, the interface state density was significantly reduced by the pretreatments, and this effect was more pronounced when the oxidizing agent injection step was skipped. However, both pretreatments increased the capacitance-equivalent oxide thickness, thereby having an adverse effect, possibly owing to a change in the composition of the interfacial layer.

Automated summary

We introduced Y-O bonds into the interfacial layer between HfO2 and Si1-xGex (x = 0, 0.15, and 0.3) to reduce the number of interfacial defects. Two different pretreatment methods involving cyclic pulses of Y(CpBut)3 and N2 were used, with or without an oxidizing agent (H2O) injection at 250 degrees C. The Y pretreatments were effective in reducing leakage current, positive flatband voltage shift, and interface state density induced by an increase in Ge concentration. However, both pretreatments increased the capacitance-equivalent oxide thickness, possibly due to a change in the composition of the interfacial layer.