Characteristic Research On SOI CMOS With Strained SiGe Channel

With the development of integrated circuit entering deep submicron, the parasitic effects of traditional body silicon CMOS and mobility mismatch are urgently to be solved. The SOI structure is used to solve the parasitic effects causing from the minishing of device dimension, and the Si/SiGe strained heterojunction is applied to overcome the shortcoming of mobility mismatch. Taking SOI structure as the substrate, the SOI MOSFET with strained SiGe channel is fabricated, which combines SOI structure and Si/SiGe heterojunction technique. The device characteristics are studied from the model establishment, single device characteristics and CMOS characteristics.The structure of full depleted 0.15μm SOI CMOS with strained SiGe channel is established in this paper. Using ISE TCAD the steady-state characteristics of single device and transient and transfer characteristics of CMOS are analyzed. In order to obtain more accuracy simulation results, the models of strained SiGe and strained Si are modified and the more precise hydrodynamic transport models are carried out. The simulation results indicate that the drive ability and circuit speed of SOI CMOS with strained SiGe channel are improved a lot, compared to traditional SOI CMOS, and the improvement is especially remarkable for PMOS. The temperature characteristics of SOI PMOS with SiGe channel are analyzed. The results indicate that drive current degenerates seriously, threshold voltage drops sharply, and leakage current increases obviously with the increasing of temperature. The self-heating effect is also studied and it can be seen that the self-heating effect is more serious in SOI PMOS with SiGe channel than in traditional SOI CMOS, and the self-heating effect decreases with the increasing of temperature. Furthermore, three novel buried structures to release self-heating are compared. The results indicate that DSOI structure is not suitable for the low voltage full depleted SOI device, and the improvement of Si3N4 DSOI on self-heating effect is not significant, and the Si3N4 buried structure is the best, but its dominance reduces with the increasing of temperature compared to SiGe SOI structure.Moreover, because of low improvement of SiGe SOI structure on NMOS the SGOI structure with high electron mobility is studied and it has the merit of large improvement in NMOS. But this structure has the shortcomings of complex manufacture process and high cost.The characteristics of deep submicron SOI CMOS with SiGe channel are simulated and analyzed, and the conclusion is good for the design and manufacture of SiGe SOI MOS devices.