Low vacuum silicon thin film solar cell and method of production

Claim 1

A method for producing semiconductor solar cells comprising the steps of: establishing a vacuum environment of low 10 -4 to high 10 -5 range; positioning a deposition substrate in said vacuum environment; introducing a gaseous plasma into said vacuum environment to replace the residual gases therein; and, depositing successive passivation and semiconductor layers onto said deposition substrate in the presence of said gaseous plasma with at least some of said semiconductor layers being doped, said semiconductor layers being deposited by evaporation with the semiconductor material forming said semiconductor layers coming from a solid source.

Claim 2

A method for producing semiconductor solar cells comprising the steps of: establishing a vacuum environment of low 10 -4 to high 10 -5 range; positioning a deposition substrate in said vacuum environment; introducing a gaseous plasma into said vacuum environment to replace the residual gases therein; and, depositing successive passivation and semiconductor layers onto said deposition substrate in the presence of said gaseous plasma with at least some of said semiconductor layers being doped, said semiconductor layers being deposited by evaporation with the semiconductor material forming said semiconductor layers coming from a solid source.

Claim 7

A method for producing a heterostructure solar cell having microcrystal silicon superposed on amorphous silicon, said method comprising the steps of: 1. positioning a steel substrate in a vacuum environment; 2. establishing a vacuum of high 10 -5 torr range and then heating the substrate to between 250° and 450° and introducing an ionized gas into said vacuum environment; 3. evaporating and depositing in sequence on the substrate the following layers of materials while a vacuum of a low 10 -4 torr range is maintained: (a) a passivation metal layer of 500 Angstroms, (b) a n-doped silicon layer of 300 Angstroms, (c) an intrinsic silicon layer of 5000 Angstroms; and, (d) a p-doped silicon layer of 30 Angstroms. 4. after deposition of the p-doped silicon layer, raising the substrate temperature to 630° C. in a time of 5 to 10 minutes which is sufficiently long to establish a thermal equilibrium, but not too long to induce a crystallization of the amorphous layer of silicon deposited in Step 3; 5. after the 630° C. temperature is reached, depositing a p-layer of microcrystal silicon of a thickness of 500 Angstroms; 6. thereafter, lowering the temperature in a hydrogen plasma ambient to 250° C. in 10 to 30 minutes; and, 7. completing the solar cell by attaching thereto a top electrode.

Claim 8

A method for producing a heterostructure solar cell having microcrystal silicon superposed on amorphous silicon, said method comprising the steps of: 1. positioning a steel substrate in a vacuum environment; 2. establishing a vacuum of high 10 -5 torr range and then heating the substrate to between 250° and 450° and introducing an ionized gas into said vacuum environment; 3. evaporating and depositing in sequence on the substrate the following layers of materials while a vacuum of a low 10 -4 torr range is maintained: (a) a passivation metal layer of 500 Angstroms, (b) a n-doped silicon layer of 300 Angstroms, (c) an intrinsic silicon layer of 5000 Angstroms; and, (d) a p-doped silicon layer of 30 Angstroms. 4. after deposition of the p-doped silicon layer, raising the substrate temperature to 630° C. in a time of 5 to 10 minutes which is sufficiently long to establish a thermal equilibrium, but not too long to induce a crystallization of the amorphous layer of silicon deposited in Step 3; 5. after the 630° C. temperature is reached, depositing a p-layer of microcrystal silicon of a thickness of 500 Angstroms; 6. thereafter, lowering the temperature in a hydrogen plasma ambient to 250° C. in 10 to 30 minutes; and, 7. completing the solar cell by attaching thereto a top electrode.