Method of making an IGFET and a protected resistor with reduced processing steps

摘要

A method of making an IGFET and a protected resistor includes providing a semiconductor substrate with an active region and a resistor region, forming a gate over the active region, forming a diffused resistor in the resistor region, forming an insulating layer over the gate and the diffused resistor, forming a masking layer over the insulating layer that covers the resistor region and includes an opening above the active region, applying an etch using the masking layer as an etch mask so that unetched portions of the insulating layer over the active region form spacers in close proximity to opposing sidewalls of the gate and an unetched portion of the insulating layer over the resistor region forms a resistor-protect insulator, and forming a source and a drain in the active region. In this manner, a single insulating layer provides both sidewall spacers for the gate and a resistor-protect insulator for the diffused resistor.