Record-low 4 m/spl Omega//spl middot/mm/sup 2/ specific on-resistance for 20V trench MOSFETs

A process is shown by which both the specific on-resistance R/sub ds,on/ and the gate-drain charge density Q/sub gd/ can be reduced. Reduction of the R/sub ds,on/ is achieved by optimizing the channel profile (p-body) towards a more box-shaped profile. The Q/sub gd/ is reduced by going to smaller trench dimensions below the I-line lithography limits, without using deep-UV lithography. For polygonal cell structures, it is shown that narrowing the trenches also gives further R/sub ds,on/ reduction. Record values for R/sub ds,on/ of 4 m/spl Omega//spl middot/mm/sup 2/ (at V/sub gs/=10V) have been obtained for a 20V Trench MOSFET with a 2 /spl mu/m cell pitch. Furthermore, for a conventional 30V Trench MOSFET, we obtained an R/sub ds,on/ of 7 m/spl Omega//spl middot/mm/sup 2/ (at V/sub gs/=10V) by a more box-shaped p-body profile.