Method for executing a reproducible glow discharge

• US 4,812,416 A
• Filed: 11/28/1986
• Issued: 03/14/1989
• Est. Priority Date: 11/28/1985
• Status: Expired due to Fees

• Current Assignee: Berthold Schum, Gerd Hewig, Jorg Worner
• Original Assignee: Berthold Schum, Gerd Hewig, Jorg Worner
• Inventors: Schum, Berthold, Worner, Jorg, Hewig, Gerd
• Primary Examiner(s): Weisstuch, Aaron
• Application Number:
  US06/936,089
• Time in Patent Office: 837 Days
• Field of Search: 29/572, 29/574, 156/626, 156/627, 156/643, 204/192.33, 136/258 AM, 136/260, 427/8, 427/39, 134/1, 134/21, 437/2, 437/4, 437/5, 437/8
• US Class Current: 438/14
• CPC Class Codes: H01L 31/03365 comprising only Cu2X / CdX heterojunctions, X being an element of Group VI of the Periodic Table
• CPC Class Codes: H01L 31/072 the potential barriers being only of the PN heterojunction type
• CPC Class Codes: H01L 31/202 including only elements of Group IV of the Periodic Table
• CPC Class Codes: Y02E 10/50 Photovoltaic [PV] energy
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product

Abstract

In order to be able to check whether or not a glow procedure is executed properly, i.e. reproducibly, the temporal course of the formation of characteristic stable reaction products is traced mass spectrometrically.

Claims

1. Method for the execution of a reproducible glow discharge process by tracing mass spectrometrically the temporal course of the partial pressure of volatile stable reaction products in the plasma with a reactant located in a glow discharge column for the manufacture of a Cu_2-x S/CdS thin film semiconductor solar cell with 0≦

x≦

1, in which the Cu_2-x S layer is exposed to a glow discharge process in a hydrogen atmosphere, which includes the steps of;

(a) reduction by the glow discharge of Cu_2-z O with 0≦

z≦

1 present on the Cu_2-x S layer and of excess sulphur ions from the Cu_2-x S layer until a highly stoichiometric Cu₂.0000 S layer is produced;

(b) formation of an inversion layer on and from the highly stoichiometric Cu₂.0000 S layer by way of adsorption of negatively charged hydrogen atoms (H^- ions) from the hydrogen atmosphere of the glow discharge; and

(c) reduction of the free surface of the inversion layer to elemental copper.

2. Method according to claim 1, wherein the reduction is executed in the positive column of the glow discharge.

3. Method according to claim 1, wherein the glow discharge process for the formation of the inversion layer occurs in an evacuated space that is first set at a pressure p˜

10^-6 mbar (10⁴ Pa) and that the space is subsequently flooded with hydrogen for attaining a pressure of 0.5 mbar (50 PA) in order to execute the glow discharge process.

4. Method according to claim 3, wherein the glow discharge process occurs at a current density of 10 μ

A/cm² of semiconductor layer at a voltage of 300 V applied between the electrodes.

5. Method according to claim 1, wherein the hydrogen atomsphere of the glow space is exchanged during the glow discharge process without altering the internal pressure.

6. Method according to claim 5, wherein the exchange occurs approximately twice per minute.

7. Method according to claim 1, wherein the temporal course of the glow process is set in such a way that the H₂ S partial pressure resulting fromthe reduction of the Cu_2-x S layer, measured in a continuously exchanging atmosphere, first increases sharply and, after reaching a maximum, decreases sharply again (range I) with the maximum being shifted toward the shorter period, followed by a gradual decrease in the H₂ S partial pressure until a minimum is reached (range II), and after which the H₂ S partial pressure increases almost continuously (range III).

8. Method according to claim 7, wherenthe ratio of the area of range I to that of range II is A_I :

A_II =(2.5+/-0.5);

1.

9. Method for the execution of a reproducible glow discharge process by tracing mass spectrometrically the temporal course of the partial pressures of volatile stable reaction products in the plasma with a reactant located in a glow discharge column for the manufacture of thin film semeconductors, wherein the temporal course of characteristic volatile hydrogen products of said semiconductors is traced and wherein the semiconductor material is SnO₂ or CuInSe₂.