Reaction apparatus and method for manufacturing a cigs absorber of a thin film solar cell

Abstract

The present invention provides an apparatus and a method for manufacturing a CIGS absorber of a thin film solar cell. The apparatus includes a supply chamber configured to provide a flexible substrate coated with precursors. The apparatus further includes a reaction chamber coupled to the supply chamber for at least subjecting the precursors on the flexible substrate to a reactive gas at a first state to form an absorber material. Additionally, the apparatus includes a gas-balancing chamber filled with the reactive gas at a second state. The gas-balancing chamber is communicated with the reaction chamber for automatically updating the first state of the reactive gas to the second state. Moreover, the apparatus includes a control system to maintain the second state of the reactive gas in the gas-balancing chamber at a preset condition and to adjust the transportation of the flexible substrate through the reaction chamber.

What is claimed is: 
     
         1 . A method for manufacturing a CIGS-based absorber of a thin film solar cell, the method comprising:
 providing a flexible substrate in a supply chamber as a wound roll, the flexible substrate being coated with precursor materials made by one of the following sequential layers: Cu/In/Ga/Se, Cu/In/Cu/Ga/Se, Cu—In alloy/Ga/Se, Cu—Ga alloy/In/Se, Cu/In—Ga alloy/Se, Cu/Ga/Cu/In/Se, Cu/Ga/In/Se, Cu—Ga alloy/Cu—In alloy/Se, Cu—Ga alloy/Cu—In alloy/Ga/Se, Cu/Cu—In alloy/Ga/Se, and Cu—Ga alloy/In/In—Ga alloy/Se;   providing a reaction chamber sequentially coupled between the supply chamber and a receiving chamber, wherein the supply chamber, the reaction chamber, and the receiving chamber are respectively sealed hermetically and the reaction chamber is further divided into a pre-heating region, a reaction region, and a cooling region respectively sealed from each other;   providing a gas-balancing chamber coupled to the reaction region with a permeation communication and a common thermal control;   introducing a Se-bearing reactive gas respectively in each of the pre-heating region, the reaction region, the cooling region, and the gas-balancing chamber;   unfolding the flexible substrate from the wound roll in the supply chamber to transport into the reaction chamber for at least subjecting the precursor materials to a selenization reaction with the Se-bearing reactive gas in the reaction region including additional Se vapor partially released from the precursor materials;   maintaining the Se-bearing reactive gas within the gas-balancing chamber at a predetermined state, the Se-bearing reactive gas including additional Se vapor in the reaction region being dynamically balanced at the same predetermined state by the permeation valve and the common thermal control during the selenization reaction to transform the precursor materials into a semiconductor absorber substantially uniformly on the flexible substrate that is continuously transported through the reaction region;   transporting the flexible substrate further out of the reaction region to the cooling region to cool the formed semiconductor absorber thereon; and   receiving the flexible substrate including the semiconductor absorber in the receiving chamber, the flexible substrate being wound into a roll.   
     
     
         2 . The method of  claim 1  wherein the gas-balancing chamber comprises a volume ranging from 10 times smaller to 10 times larger than volume of the reaction region. 
     
     
         3 . The method of  claim 1  wherein the gas-balancing chamber is coupled to the reaction region from a location above the reaction region to utilize gravity effect for assisting a dynamic balancing of the Se-bearing reactive gas in the reaction region and in the gas-balancing chamber. 
     
     
         4 . The method of  claim 1  wherein maintaining the Se-bearing reactive gas within the gas-balancing chamber at a predetermined state comprises maintaining a predetermined pressure using an inlet valve connected to a gas-source, an evacuation valve for exhausting extra gas, and optionally an outlet valve connected to a standby chamber, and maintaining a predetermined temperature the same as the reaction region by a control system assisted by feedback information received from a plurality of sensor devices. 
     
     
         5 . The method of  claim 4  wherein the plurality of sensor devices comprises at least a temperature sensor, a concentration detector, and a pressure sensor. 
     
     
         6 . The method of  claim 1  wherein providing the reaction chamber comprises configuring a horizontal portion of the pre-heating region to couple with the supply chamber, changing the horizontal portion to an ascending portion at a first turning position by a first angle, extending the ascending portion of the pre-heating region to an ascending portion of the reaction region up to an apex position, changing the ascending portion of the reaction region to a descending portion of the reaction region at the apex position by a second angle, extending the descending portion of the reaction region to a descending portion of the cooling region, and changing the descending portion of the cooling region to a horizontal portion of the cooling region at a second turning position by a third angle, the first angle being set to a range from 0 degree up to 45 degrees, the second angle being substantially equal to 2× of the first angle, the third angle being substantially equal to the first angle. 
     
     
         7 . The method of  claim 6  further comprising regulating substrate tension during its transportation by causing a radial motion of a regulating roller disposed at each one of the first turning position, the apex position, and the second turning position against the flexible substrate. 
     
     
         8 . The method of  claim 7  wherein regulating substrate tension is controlled by detecting the length change of the flexible substrate using a distance sensor to drive the radial motion of the regulating roller. 
     
     
         9 . The method of  claim 1  wherein the reaction chamber comprises at least two pairs of auxiliary rollers for clamping and transporting the flexible substrate at two separate locations in an elongated channel having a height limited to a range between 3 mm and 30 mm. 
     
     
         10 . The method of  claim 9  wherein each pair of auxiliary rollers is configured to hermetically separate the reaction region from either the pre-heating region or the cooling region. 
     
     
         11 . The method of  claim 1  further comprising providing separate heating components including thermal insulation materials configured to wrap around the pre-heating region, the reaction region of the reaction chamber, and the gas-balancing chamber, to independently control the pre-heating region at a first temperature, the reaction region at a second temperature, and the gas-balancing chamber at a third temperature, the second temperature being set to be greater than the first temperature with a step profile and substantially equal to the third temperature.