Semiconductor Transport

Abstract

Performance of electron devices such as MOSFETs is characterized by parameters such as mobility, transconductance, leakage current, etc. These parameters are some particular aspects or concrete representation of carrier transport properties in semiconductor structures. Device performance enhancement by strain is rooted from strain altered carrier transport properties. Based on the band structures we discussed in earlier chapters, we will discuss some basic transport models in this chapter to understand how strain changes electron/hole transport, to reach theoretical understanding of strain effects on device performance. First in Sect. 6.2 a qualitative overview is given for readers who want just to dabble in transport theories and strainenhanced mobility in Si MOSFETs. Then in Sects. 6.3 and 6.4 we discuss the various scattering mechanisms in semiconductors and construct a general formulation to treat scattering processes. Boltzmann equation is introduced afterward in Sect. 6.5 to calculate the carrier mobility. In low-dimensional semiconductor structures, scattering processes are significantly different from that of bulk. The new features of scattering in 2D systems are particularly discussed in Sect. 6.6. The strain effects on transport are discussed and summarized in Sect. 6.7.