Direct Silicon Bond
ESTIMATED TO BE DOUBLE SOI OR APPROXIMATELY $3.4 BILLION BY 2010
One of the most promising substrate options for sub 65-nm CMOS development is hybrid orientation direct bonded silicon-on-silicon wafers. Different crystal orientations may then be utilized to independently tailor NMOS and PMOS device performance enhancement. Generally referred to as a hybrid-orientation substrate, these engineered substrates necessarily use layer-transfer processes to laminate silicon crystal layers of different orientation. The approach relies on the well-known dependence of effective MOS device carrier mobility to silicon surface crystal orientation. Generally, the (100) silicon crystal surface orientation is advantageous for fabricating NMOS devices while the effective PMOS mobility is nearly doubled for PMOS devices processed on a (110) crystal surface orientation.
SiGen's plasma activated bonding (PAB) and room temperature controlled cleaving technology (rT-CCP™) gives hybrid substrate designers detailed control of the chemical and physical properties of the bond interface in the formation of direct silicon bond (DSB) substrates.
DSB wafers have the same characteristics as standard bulk silicon wafers with the notable exception of better mobility. DSB, therefore, can be a direct substitute for bulk silicon for high performance semiconductor devices.
Cross-Section Transmission Electron Micrograph (TEM) of the Bond Interface