Semiconductor device and fabrication method thereof

A fabrication method for a semiconductor device, wherein the semiconductor device comprises:

• a substrate having a STI structure;
• a first polysilicon structure layer, an isolation dielectric layer, and a second polysilicon structure layer sequentially stacked on the STI structure;
• wherein the first polysilicon structure layer is undoped polysilicon;
• the second polysilicon structure layer is heavily boron-doped polysilicon;
• contact hole structures are formed on the first polysilicon structure layer to monitor a target doping concentration of boron in the first polysilicon structure layer during high-concentration boron ion implantation and subsequent annealing activation of the second polysilicon structure layer;
• the contact hole structures are disposed on both sides of the first polysilicon structure layer and spaced apart from the second polysilicon structure layer, respectively;
• the contact hole structures contain contact electrodes connecting electrical potential of the first polysilicon structure layer out and measuring resistivity of the first polysilicon structure layer after boron doping;
• the first polysilicon structure layer has a predetermined length about 10 μm, and the isolation dielectric layer has a predetermined thickness about 2 nm;
• or
• wherein the semiconductor device comprises:
• a substrate having a STI structure;
• a first polysilicon structure layer, an isolation dielectric layer, and a second polysilicon structure layer sequentially stacked on the STI structure;
• wherein the first polysilicon structure layer is undoped polysilicon;
• the second polysilicon structure layer is heavily boron-doped polysilicon;
• contact hole structures are formed on the first polysilicon structure layer to monitor a target doping concentration of boron in the first polysilicon structure layer during high-concentration boron ion implantation and subsequent annealing activation of the second polysilicon structure layer;
• the contact hole structures are disposed on both sides of the first polysilicon structure layer and spaced apart from the second polysilicon structure layer, respectively;
• the contact hole structures contain contact electrodes connecting electrical potential of the first polysilicon structure layer out and measuring resistivity of the first polysilicon structure layer after boron doping;
• the first polysilicon structure layer has a predetermined length about 10 μm, and the isolation dielectric layer has a predetermined thickness about 2 nm, and the isolation dielectric layer comprises a silicon dioxide film;
• wherein the fabrication method comprises:
• providing a substrate for integrated circuit fabrication, forming a STI structure on the substrate;
• forming a first polysilicon structure layer on the STI structure;
• forming an isolation dielectric layer on the first polysilicon structure layer, the isolation dielectric layer covering the first polysilicon structure layer;
• forming a second polysilicon structure layer on the isolation dielectric layer, corresponding to the first polysilicon structure layer;
• performing high-concentration boron ion implantation into the second polysilicon structure layer, and subsequently annealing activation;
• forming contact hole structures on the first polysilicon structure layer, that monitors a target doping concentration of boron in the first polysilicon structure layer through the contact hole structures;
• and
• optimizing annealing activation parameters based on the target doping concentration.