Forming structures on resistive substrates

A method of forming a substrate, the method comprising:

• forming an intrinsic region;
• forming a first region having a first resistivity, for accommodating a field effect transistor;
• forming a second region having a second resistivity, for accommodating an npn subcollector of a bipolar transistor device and triple well;
• forming a third region having a third resistivity, for accommodating a passive device;
• and
• forming a fourth region, substantially without implantation, to provide low perimeter capacitance for devices, the fourth region comprising a portion of the intrinsic region;
• wherein the resistivity of the first region is between 1 ohm-cm and 100 ohm-cm and includes dopant materials to lower its resistivity with respect to the intrinsic region, the resistivity of the second region is between 0.001 and 0.1 ohm-cm, the resistivity of the third region is between 500 and 5000 ohm-cm and includes dopant materials to increase its resistivity with respect to the intrinsic region, and the resistivity of the fourth region and the intrinsic region is about 1000 ohm-cm.

A method of forming a semiconductor device, the method comprising:

• forming a substrate, the substrate including:
• an intrinsic region;
• a first region having a first resistivity, for accommodating a field effect transistor;
• a second region having a second resistivity, for accommodating an npn subcollector of a bipolar transistor device and triple well;
• a third region having a third resistivity, for accommodating a passive device;
• and
• a fourth region, substantially without implantation, to provide low perimeter capacitance for devices, the fourth region comprising a portion of the intrinsic region;
• wherein the resistivity of the first region is between 1 ohm-cm and 100 ohm-cm and includes dopant materials to lower its resistivity with respect to the intrinsic region, the resistivity of the second region is between 0.001 and 0.1 ohm-cm, the resistivity of the third region is between 500 and 5000 ohm-cm and includes dopant materials to increase its resistivity with respect to the intrinsic region, and the resistivity of the fourth region and the intrinsic region is about 1000 ohm-cm.