RF switch on high resistive substrate

A device comprising:

• a semiconductor substrate;
• a deep n-well region in the semiconductor substrate;
• a p-well region over and contacting the deep n-well region, wherein the semiconductor substrate comprises:
• a top portion overlying the p-well region;
• and
• a bottom portion underlying the deep n-well region, wherein the top portion and the bottom portion are of p-type, and wherein both the top portion and the bottom portion have a resistivity greater than about 5,000 ohm-cm;
• a Radio Frequency (RF) switch comprising:
• a gate dielectric over the top portion of the semiconductor substrate;
• a gate electrode over the gate dielectric;
• and
• a source region and a drain region extending into the top portion of the semiconductor substrate, wherein the source region and the drain region are spaced apart from the p-well region by the top portion of the semiconductor substrate;
• and
• an RF passive device overlying and electrically coupled to the RF switch.

A device comprising:

• a semiconductor substrate;
• a well region in the semiconductor substrate;
• a gate stack overlapping a top portion of the semiconductor substrate spacing the gate stack apart from the well region, with the top portion of the semiconductor substrate having a resistivity higher than about 5,000 ohm-cm;
• a gate spacer on a sidewall of the gate stack;
• a source/drain region on a side of the gate stack, wherein an edge of the source/drain region is aligned to an outer edge of the gate spacer;
• a silicide region over and contacting the source/drain region;
• and
• a dielectric layer overlapping and in physical contact with the source/drain region, wherein the dielectric layer comprises an outer edge aligned to an inner edge of the silicide region, and an inner edge contacting the outer edge of the gate spacer.