1. A secure transaction method, comprising the steps of:
establishing an electronically accessible verification site authorized by the holder of authentication credentials;
receiving a request for goods or services at a merchant using the credentials, but wherein the credentials are not physically presented to the merchant;
accessing the verification site by the merchant to determine whether the request for goods or services is an authorized transactions;
sending an electronic authorization communication by the verification site to the holder of the credentials, the message including information indicative of the transaction; and
transmitting, by the holder of the credentials, an approval communication if the transaction is approved by the holder of the credentials.
2. The method of claim 1, wherein the verification site is an electronic mail account.
3. The method of claim 2, wherein electronic mail account was established by the merchant.
4. The method of claim 1, wherein an authorization message is sent from the site to the merchant in response to the step of accessing the verification site by the merchant.
5. The method of claim 4, wherein the authorization message is automatically generated.
6. The method of claim 4, wherein the authorization message is manually generated within a predetermined period of time.
7. The method of claim 4, wherein request for goods or services, the step of accessing the verification site, the authorization message, or any combination thereof, are encrypted.
8. The method of claim 7, wherein the encryption is implemented using an algorithm specific to the holder or an authorized user of the credentials.
9. The method of claim 4, wherein request for goods or services, the step of accessing the verification site, the authorization message, or any combination thereof, include routing information for future use.
10. The method of claim 1, wherein the step of accessing the verification site by the merchant causes an icon or window to appear in a web browser.
11. The method of claim 1, wherein the verification site is wirelessly accessible.
12. The method of claim 11, wherein the site is accessible through a cellular telephone, personal digital assistant, or other mobile device.
13. The method of claim 1, wherein the information indicative of the transaction includes information identifying the merchant.
14. The method of claim 1, wherein the information indicative of the transaction includes information identifying the goods or services.
15. The method of claim 1, wherein the information indicative of the transaction includes the cost of the transaction.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
What is claimed is:
1. A process for producing a photovoltaic cell, which comprises
a step of forming a dopant diffusion preventing mask on a surface of a semiconductor substrate by adhering a material for the dopant diffusion preventing mask in a pattern state to the semiconductor substrate surface, and
a step of forming a first dopant layer on a portion not covered by the dopant diffusion preventing mask by a first gas phase diffusion.
2. A process according to claim 1, which further comprises
a step of removing the dopant diffusion preventing mask after the first dopant layer forming step, and
a step of forming a second dopant layer by a second gas phase diffusion on the region from which the dopant diffusion preventing mask is removed.
3. A process according to claim 1, wherein the dopant diffusion preventing mask contains a dopant so as to function as a solid phase diffusion source, and a third dopant layer is formed under the dopant diffusion preventing mask.
4. A process according to claim 1, wherein the semiconductor substrate is made of silicon, the dopant diffusion preventing mask is made of an electrically insulating material and has an opening, said process further comprises after the step of forming the first dopant layer
a step of coating a metal containing a dopant which decides a type of electroconductivity in the opening in the dopant diffusion preventing mask,
a step of converting the first dopant layer to a dopant layer having an opposite electroconductivity by firing, and
a step of forming a metallic electrode for the impurity layer having the opposite electroconductivity.
5. A process according to claim 1, wherein the semiconductor substrate is made of silicon, the dopant diffusion preventing mask is made of an electrically insulating material and has an opening, said process further comprises after the step of forming the first dopant layer
a step of coating aluminum containing a dopant which decides a type of electroconductivity in the opening in the dopant diffusion preventing mask,
a step of converting the first dopant layer to a p-type dopant layer by firing, and
a step of forming an aluminum electrode for the p-type dopant layer.
6. A process according to claim 1, wherein a dopant layer having an opposite electroconductivity to the first dopant layer is formed before the step of formation of the dopant diffusion preventing mask.
7. A process according to claim 1, wherein the semiconductor substrate has a through-hole which penetrates from a front surface to a rear surface and said process comprising
a step of forming the first dopant layer on the front surface and rear surface of the semiconductor substrate having no dopant diffusion preventing mask and inside wall of the through-hole by the first gas phase diffusion.
8. A process for producing a photovaltaic cell, which comprises
a step of forming a dopant diffusion preventing mask on a surface of a semiconductor substrate by adhering a material for the dopant diffusion preventing mask in a pattern state to the semiconductor substrate surface,
a step of forming a solid phase diffusion source layer, and
a step of forming a first dopant layer on the portion having no dopant diffusion preventing mask by solid phase diffusion from the solid phase diffusion source layer.
9. A process according to claim 8, wherein the dopant diffusion preventing mask contains a dopant so as to function as a solid phase diffusion source, and a second dopant layer is formed under the dopant diffusion preventing mask.
10. A process according to claim 1 or 8, wherein the material for the dopant diffusion preventing mask is adhered to the semiconductor substrate by a printing method.
11. A process according to claim 1 or 8, wherein the material for the dopant diffusion preventing mask contains silicon oxide or silicon nitride.
12. A process according to claim 1, wherein the material for the dopant diffusion preventing mask has a viscosity of 500,000 cp to 1,000,000 cp.
13. A process according to claim 8, wherein the material for the dopant diffusion preventing mask and a material for the solid phase diffusion source layer have a viscosity of 500,000 cp to 1,000,000 cp.
14. A photovoltaic cell comprising a semiconductor substrate, an electrically insulating material layer formed on the semiconductor substrate by a coating method, and electrodes formed on openings of the electrically insulating material layer.
15. A photovoltaic cell according to claim 14, which further comprises a first dopant layer formed on outside of the electrically insulating material layer on the semiconductor substrate, and a second dopant layer having an opposite electroconductivity to the first dopant layer and formed in the opening of the electrically insulating material layer, said second dopant layer containing p-type dopant and n-type dopant.
16. A photovoltaic cell according to claim 15, wherein the fist dopant layer is an n-type dopant layer, the second dopant layer is a p-type dopant layer, the semiconductor substate is made of silicon, the electrode is made of aluminum, and said p-type dopant layer contains aluminum and an n-type dopant.
17. A photovoltaic cell comprising a semiconductor substrate, and a dopant layer formed on the semiconductor substrate and having different heights by 10 m or more in periphery shape.
18. A photovoltaic cell according to claim 17, which further comprises a through-hole penetrating the semiconductor substrate from a front surface to a rear surface, and a dopant layer having the same electroconductivity and connecting the front surface, the rear surface and inside of through-hole.