Epitaxial Growth of Si/Si1-xGex Films on Corrugated Substrates for Improved pMOSFET Performance

The quasi-planar segmented-channel MOSFET (SegFET) design provides an evolutionary pathway for continued CMOS technology scaling [1], and can be fabricated using a conventional process flow starting with a corrugated substrate [2]. Fig. 1 shows a schematic plan view and cross-sectional views of the SegFET structure, whose channel region consists of parallel stripes of equal width (W_stripe) isolated by very shallow trench isolation (VSTI) dielectric material which extends below the source/ drain extensions but which can be much shallower than the STI dielectric material used to isolate transistors. The fringing electric fields through the VSTI regions provide for enhanced gate control of the channel potential, so that the SegFET exhibits better short channel behavior compared to the conventional MOSFET [2]. To achieve improved on-state performance, mobility enhancement techniques can be employed; for example, silicon-germanium (Si_1-xGe_x) can be used as the channel material to enhance p-channel MOSFET performance [3-4]. This work investigates the selective epitaxial growth of Si and Si_1-xGe_x layers to form corrugated-Si/Si_1-xGe_x substrates for enhanced p-channel SegFET performance.