Specific Process Knowledge/Thermal Process/Dope with Phosphorus: Difference between revisions
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'''Feedback to this page''': '''[mailto:labadviser@nanolab.dtu.dk?Subject=Feed%20back%20from%20page%20http://labadviser.nanolab.dtu.dk/index.php/Specific_Process_Knowledge/Thermal_Process/Dope_with_Phosphorus click here]''' | '''Feedback to this page''': '''[mailto:labadviser@nanolab.dtu.dk?Subject=Feed%20back%20from%20page%20http://labadviser.nanolab.dtu.dk/index.php/Specific_Process_Knowledge/Thermal_Process/Dope_with_Phosphorus click here]''' | ||
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==Test of the Phosphorus Predep furnace== | ==Test of the Phosphorus Predep furnace== | ||
====Purpose==== | ====Purpose==== | ||
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Looking at the "SIMS Measurement After Drive-in Process at 1050 <sup>o</sup>C" graph, it can be seen that the two curves "Pre-dep at 950 <sup>o</sup>C" and "Pre-dep at 1000 <sup>o</sup>C" are crossing each other, but according to the theory they should not do that. Only one wafer has been measured so there is not that much statistical data to verify it with. | Looking at the "SIMS Measurement After Drive-in Process at 1050 <sup>o</sup>C" graph, it can be seen that the two curves "Pre-dep at 950 <sup>o</sup>C" and "Pre-dep at 1000 <sup>o</sup>C" are crossing each other, but according to the theory they should not do that. Only one wafer has been measured so there is not that much statistical data to verify it with. | ||
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==Test of the Phosphorus Predep furnace== | ==Test of the Phosphorus Predep furnace== | ||
====Purpose==== | ====Purpose==== | ||
To find the result of a specific process using the Phosphorus Predep furnace (A4) followed by a drive in and oxidating the substrate in the Phosphorus drive in furnace (A3). | To find the result of a specific process using the Phosphorus Predep furnace (A4) followed by a drive in and oxidating the substrate in the Phosphorus drive in furnace (A3). | ||
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* RCA cleaning of the test wafer (p-type, 1-20 Ωcm) and the dummy wafers | * RCA cleaning of the test wafer (p-type, 1-20 Ωcm) and the dummy wafers | ||
* Phosphorus pre-deposition in the Phosphorus Pre-dep furnace (A4). | * Phosphorus pre-deposition in the Phosphorus Pre-dep furnace (A4). | ||
** Recipe: " | ** Recipe: "POCL900" | ||
** Temperature: 900 °C | ** Temperature: 900 °C | ||
** Time: 15 min phosphorus pre-dep and 20 min annealing/N<sub>2</sub> post purge | ** Time: 15 min phosphorus pre-dep and 20 min annealing/N<sub>2</sub> post purge | ||
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The sheet resistance was 54 Ωsq in the center of the wafer and 45-48 Ωsq in the edge of the wafer. This correspond quite good to the results that previously had been obtained for the furnace as can be seen on this LabAdviser page. | The sheet resistance was 54 Ωsq in the center of the wafer and 45-48 Ωsq in the edge of the wafer. This correspond quite good to the results that previously had been obtained for the furnace as can be seen on this LabAdviser page. | ||
====Notes about the | ====Notes about the POCL recipes==== | ||
A new recipe called | A new recipe for POCL doping called was made, after the POCl<sub>3</sub> line was modified. The N<sub>2</sub> high flow (3 SLM) is on all the time through the recipe. There is a 2 min pre-purge with first N2 low (150 sccm) through the POCl3 bubbler, i.e. with the valves v4a and v4b closed, and then with O2 (0.50 SLM), before the pre-deposition time starts. After the pre-deposition, an N2 low post-purge (500 sccm) is done for 2 minutes with v4a and v4b closed. | ||
For safety reasons it is important that the POCl<sub>3</sub> is completely removed from the furnace, before it is opened to load or unload wafers. | For safety reasons it is important that the POCl<sub>3</sub> is completely removed from the furnace, before it is opened to load or unload wafers. | ||
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With 150 sccm N2 low through 25°C POCl<sub>3</sub> liquid + 3 slm N<sub>2</sub> high + 0.5 slm O<sub>2</sub>, 3300 ppm Cl<sub>2</sub> is created in the tube. These 3300 ppm Cl<sub>2</sub> must be diluted to less than 0.5 ppm (the TLV value). | With 150 sccm N2 low through 25°C POCl<sub>3</sub> liquid + 3 slm N<sub>2</sub> high + 0.5 slm O<sub>2</sub>, 3300 ppm Cl<sub>2</sub> is created in the tube. These 3300 ppm Cl<sub>2</sub> must be diluted to less than 0.5 ppm (the TLV value). | ||
The tube diameter is 16 cm and the length without ball valve is about 125 cm, and thus the volume is about 25 L. After the phosphorus pre-deposition step, the N<sub>2</sub> high flow (3 SLM) is on during the annealing/N<sub>2</sub> post purge, the cooling and a waiting step. The time for the waiting step is 30 minutes, so even if the annealing time is set to 0 minutes, and the furnace does not have to cool down, there will still be an N<sub>2</sub> high flow for 30 minutes to remove the POCl<sub>3</sub> from the furnace. The waiting time is the same in the abort recipe that is activated, if the | The tube diameter is 16 cm and the length without ball valve is about 125 cm, and thus the volume is about 25 L. After the phosphorus pre-deposition step, the N<sub>2</sub> high flow (3 SLM) is on during the annealing/N<sub>2</sub> post purge, the cooling and a waiting step. The time for the waiting step is 30 minutes, so even if the annealing time is set to 0 minutes, and the furnace does not have to cool down, there will still be an N<sub>2</sub> high flow for 30 minutes to remove the POCl<sub>3</sub> from the furnace. The waiting time is the same in the abort recipe that is activated, if the POCL doping recipe is aborted. | ||
The | The recipe can be modified with other temperatures and names. | ||