The Channel Backscattering Characteristics of Sub-100nm CMOS Devices with Different Channel/Substrate Orientations

The channel backscattering and injection velocity of carriers in advanced CMOS devices are the two key parameters for achieving high drain current enhancement. For the first time, an extensive study of these transport parameters for different substrate orientations has been evaluated for both nMOSFET and pMOSFET. By suitably choosing the substrate orientation, it may achieve a reduced backscattering and an increased injection velocity, which is preferable for designing high performance logic CMOS devices. Results show that, in pMOSFET, (110) substrate is preferred and current enhancement can be greatly enhanced in the <112> channel. In comparison, (110) substrate in nMOSFET has an adverse effect in reducing driving current as a result of poorer transport characteristics. Therefore, (100) substrate is expected for nMOSFET design. A guideline is then summarized for the optimum design of high performance CMOS devices.