Method for doping a GaN-base semiconductor
View Patent ↗The method for doping a GaN-base semiconductor to fabricate a p-n junction includes a first step consisting in providing a substrate including a GaN-base semiconductor material layer covered by a silicon-base mask. The method includes a second step of performing implantation of impurities in the mask so as to transfer additional dopant impurities of Si type by diffusion from the mask to the semiconductor material layer to form an n-type area adjacent to a p-type area. Configured heat treatment is then performed to activate the dopant impurities and the additional dopant impurities.
1. A method for doping a semiconductor GaN-base to fabricate a p-n junction, comprising the following steps:
providing a substrate comprising a GaN-base semiconductor material layer covered by a silicon-base mask,
implanting dopant impurities in the mask so as to transfer additional dopant impurities of Si type by diffusion from the mask to the GaN-base semiconductor material layer to form an n-type area adjacent to a p-type area,
performing thermal annealing configured to activate the dopant impurities and the additional dopant impurities.
2. The method for doping a semiconductor according to claim 1 , wherein the mask partially covers the substrate so as to define an area covered by the mask and an uncovered area.
3. The method for doping a semiconductor according to claim 1 , wherein the dopant impurities are of p-type.
4. The method for doping a semiconductor according to claim 1 , wherein the mean implantation depth of the dopant impurities is located at a distance at least equal to 300 nm from the interface between the mask and the semiconductor material layer so as to incorporate additional dopant impurities in the semiconductor material layer.
5. The method for doping a semiconductor according to claim 1 , comprising a deposition step of a cap layer performed before the heat treatment step.
6. The method for doping a semiconductor according to claim 5 , wherein the deposition step of the cap layer is performed before the implantation step of the dopant impurities.
7. The method for doping a semiconductor according to claim 5 , wherein deposition of the cap layer is performed after the implantation step of the dopant impurities and of the additional dopant impurities.
8. The method for doping a semiconductor according to claim 5 , wherein the material of the cap layer is chosen from aluminium oxide, aluminium nitride, silicon oxide, or silicon nitride of SixNy type, amorphous silicon and compounds of HfSixOy type.
9. The method for doping a semiconductor according to claim 5 , comprising a take-off step of the cap layer by etching after the heat treatment.
10. The method for doping a semiconductor according to claim 1 , wherein the implantation step is performed at a temperature comprised between 15 and 700° C.
11. The method for doping a semiconductor according to claim 1 , wherein the heat treatment step is a combination of at least two anneals of different durations and temperatures.
12. The method for doping a semiconductor according to claim 11 , wherein at least one of the anneals is performed at a temperature of more 1000° C.
13. The method for doping a semiconductor according to claim 1 , wherein the thickness of the mask is comprised between 2 and 400 nm.
14. The method for doping a semiconductor according to claim 1 , wherein the thickness of the semiconductor material layer is comprised between 5 nm and 10 μm.