Controlled isotropic doping of semiconductor materials

Claim 1

A method of doping selected areas of semiconductor material comprising the steps of providing a substrate of semiconductor material having areas to be doped, said areas including contours comprising trenches and mesas, then depositing, by means of plasma enhanced low pressure chemical vapor deposition, a predetermined thickness of a dopant carrier layer of amorphous semiconductor material including a predetermined amount of dopant therein, upon the substrate areas to be doped, the dopant carrier layer being substantially uniformly deposited to the same thickness over all the contours, said step of depositing being carried out at a temperature in the range of 20° C. to 600° C. so as to prevent the dopant from being driven out of said dopant carrier layer and into said areas to be doped, and subsequently driving the dopant out of the carrier layer and into said areas to be doped in a controlled manner by annealing the substrate at a elevated temperature for a time sufficient to cause a predetermined amount of the dopan to enter said areas to be doped.

Claim 2

A method of doping selected areas of semiconductor material comprising the steps of providing a substrate of semiconductor material having areas to be doped, said areas including contours comprising trenches and mesas, then depositing, by means of plasma enhanced low pressure chemical vapor deposition, a predetermined thickness of a dopant carrier layer of amorphous semiconductor material including a predetermined amount of dopant therein, upon the substrate areas to be doped, the dopant carrier layer being substantially uniformly deposited to the same thickness over all the contours, said step of depositing being carried out at a temperature in the range of 20° C. to 600° C. so as to prevent the dopant from being driven out of said dopant carrier layer and into said areas to be doped, and subsequently driving the dopant out of the carrier layer and into said areas to be doped in a controlled manner by annealing the substrate at a elevated temperature for a time sufficient to cause a predetermined amount of the dopan to enter said areas to be doped.

Claim 14

A method of doping selected areas of semiconductor material comprising the steps of providing a substrate of semiconductor material having areas to be doped, then depositing, upon the substrate areas to be doped, a predetermined thickness of a dopant carrier layer of either amorphous silicon or amorphous germanium including a predetermined amount of dopant atoms therein, said dopant being selected from the group consisting of boron, phosphorus and arsenic, the dopant carrier layer being substantially uniformly deposited to the same thickness over all contours of the substrate, including trench and mesa sidewalls, said step of depositing being carried out at a temperature in the range of 20° C. to 600° C. so as to prevent the dopant from being driven out of said dopant carrier layer and into said areas to be doped, and subsequently driving the dopant atoms out of the carrier layer and into said areas to be doped, said step of driving being accomplished by annealing the substrate at a temperature on the order of 1000° C. for a time sufficient to cause a predetermined amount of the dopant to enter said areas to be doped.

Claim 15

A method of doping selected areas of semiconductor material comprising the steps of providing a substrate of semiconductor material having areas to be doped, then depositing, upon the substrate areas to be doped, a predetermined thickness of a dopant carrier layer of either amorphous silicon or amorphous germanium including a predetermined amount of dopant atoms therein, said dopant being selected from the group consisting of boron, phosphorus and arsenic, the dopant carrier layer being substantially uniformly deposited to the same thickness over all contours of the substrate, including trench and mesa sidewalls, said step of depositing being carried out at a temperature in the range of 20° C. to 600° C. so as to prevent the dopant from being driven out of said dopant carrier layer and into said areas to be doped, and subsequently driving the dopant atoms out of the carrier layer and into said areas to be doped, said step of driving being accomplished by annealing the substrate at a temperature on the order of 1000° C. for a time sufficient to cause a predetermined amount of the dopant to enter said areas to be doped.