A new vertical power MOSFET structure with extremely reduced on-resistance

A new vertical power MOSFET structure called rectangular-grooved MOSFET (RMOS) is proposed, in which the vertical channels are provided along the sidewalls of the rectangular grooves formed by a reactive ion-beam etching (RIBE) technique. The structure is characterized by reduced ON-resistance and high packing density. The relationship between the ON-resistance and the packing density in the new structure is calculated. It is demonstrated that the structure essentially possesses a lower ON-resistance per unit area than VMOS and DMOS structures. Experimental results are also described in detail.