Semiconductor device and method of manufacturing the same
View Patent ↗Provided is a semiconductor device including, on the same semiconductor substrate, a transistor element, a capacitor, and a resistor. The capacitor is formed on an active region, and the resistor is formed on an element isolation region, both formed of the same polysilicon film. By CMP or etch-back, the surface is ground down while planarizing the surface until a resistor has a desired thickness. Owing to a difference in height between the active region and the element isolation region, a thin resistor and a thick upper electrode of the capacitor are formed to prevent passing through of a contact.
1. A semiconductor device, comprising:
a semiconductor substrate;
a transistor element, a capacitor, and a resistor formed on the same semiconductor substrate;
a first active region, a second active region, and an element isolation having a surface larger in height than a surface of the first active region and a surface of the second active region, the first active region, the second active region, and the element isolation region being disposed on the semiconductor substrate;
a well region of a first conductivity type formed in the first active region along a main surface of the semiconductor substrate;
a gate oxide film disposed on the well region;
a gate electrode disposed on the gate oxide film, and a lower electrode for the capacitor disposed on the second active region, the gate electrode and the lower electrode being formed of a first polysilicon film;
a source region and a drain region both having a second conductivity type disposed in a surface of the well region so as to sandwich the gate electrode;
a capacitor insulator disposed on the lower electrode; and
an upper electrode for the capacitor and having impurities of the second conductivity type disposed on the capacitor insulator, and a resistor having impurities of the first conductivity type disposed on the element isolation region, the upper electrode and the resistor being formed of a second polysilicon film, wherein:
the second polysilicon film forming the resistor has a thickness smaller than a thickness of the second polysilicon film forming the upper electrode and the thickness difference therebetween is determined depending on the difference between the surface heights of the first active region and the element isolation region and on a thickness of the first polysilicon film; and
the resistor is positioned so that an upper surface
thereof is one of larger in height than an upper surface of the gate electrode and equal in height to the upper surface of the upper electrode.