Frontside micromachining using porous-silicon sacrificial-layer technologies

Several electro-and photo-electrochemical processes are pointed out which allow silicon microstruc tures to be formed within ion-implanted silicon wafers. It is shown how different lateral and vertical doping profiles can be used to anodize selectively parts of the ion-implanted silicon wafers, creating isolated regions of porous silicon. After removal of the porous silicon in diluted KOH, micromachined structures emerge at the front surface of the silicon wafers which entirely consist of low-stress bulk crystalline silicon.