Method for modifying the doping level of a silicon layer

A method for fabricating an adjustable resistor by modifying a doping level of a selected silicon region among a plurality of silicon regions, each silicon region having a first doping level, including the steps of:

• coating said plurality of silicon regions with a refractory metal silicide layer that includes a first portion and a second portion, such that an uncovered portion of the plurality of silicon regions exists between the first portion and the second portion of the silicide layer;
• heating an interface region between the selected silicon region and the silicide layer to a selected temperature;
• and
• causing, by said heating step, a doping level of the selected silicon region to decrease from the first doping level to a second doping level different than the first doping level due to migration, or outdiffusion, of dopants contained in the plurality of silicon regions toward the silicide layer;
• thereby causing a resistance between the first portion and the second portion of the silicide layer to increase so as to determine a resistance of the adjustable resistor.

A method for fabricating an adjustable resistor, including the steps of:

• providing a doped silicon region having a first end and a second end;
• coating each end of the silicon region with a silicide;
• heating an interface region between the silicon region and the silicide to cause a migration of dopants in the doped silicon region toward the first and second ends of the doped silicon region, said migration decreasing a doping level of the doped silicon region;
• and
• performing said heating step for a selected time to change the doping level of the silicon region from a first doping level to a second doping level different than the first doping level, to vary a resistance of the adjustable resistor.

A method for fabricating an adjustable resistor including modifying a doping level of a doped silicon region comprising the steps of:

• providing the doped silicon region of a first conductivity type in a semiconductor material layer of a second conductivity type:
• forming a first silicide layer disposed above a first end of the doped silicon region;
• forming a second silicide layer disposed above a second end of the doped silicon region;
• the first and second silicide layers overlaying the first end and the second end of the doped silicon region so that an uncovered portion of the doped silicon region exists therebetween;
• applying heat to at least one of the first silicide layer and the second silicide layer to vary the doping level of the doped silicon region, and
• controlling said heating step to achieve a modified doping level different than an initial doping level of the doped silicon region so as to determine a resistance of the adjustable resistor.