Methods of forming zinc oxide based II-VI compound semiconductor layers with shallow acceptor conductivities

• US 7,829,376 B1
• Filed: 04/07/2010
• Issued: 11/09/2010
• Est. Priority Date: 04/07/2010
• Status: Expired due to Fees

• Current Assignee: LumenZ, Inc
• Original Assignee: LumenZ, Inc
• Inventors: Adekore, Bunmi T., Davis, Robert F., Pierce, Jonathan M.
• Primary Examiner(s): SMITH, BRADLEY
• Application Number:
  US12/755,499
• Time in Patent Office: 216 Days
• Field of Search: 438/104
• US Class Current: 438/104
• CPC Class Codes: H01L 21/02554 Oxides
• CPC Class Codes: H01L 21/02565 Oxide semiconducting materials not being Group 12/16 materials, e.g. ternary compounds
• CPC Class Codes: H01L 21/02579 P-type
• CPC Class Codes: H01L 21/02581 Transition metal or rare earth elements
• CPC Class Codes: H01L 21/0262 Reduction or decomposition of gaseous compounds, e.g. CVD
• CPC Class Codes: H01L 21/02623 Liquid deposition

Abstract

A p-type ZnO-based II-VI compound semiconductor layer has silver, potassium and/or gold dopants therein at a net p-type dopant concentration of greater than about 1×10¹⁷ cm⁻³. A method of forming the layer includes using an atomic layer deposition (ALD) technique. This technique includes exposing a substrate to a combination of gases: a first reaction gas containing zinc at a concentration that is repeatedly transitioned between at least two concentration levels during a processing time interval, a second reaction gas containing oxygen and a p-type dopant gas containing at least one p-type dopant species selected from a group consisting of silver, potassium and gold. A concentration of oxygen in the second reaction gas may also be repeatedly transitioned between at least two concentration levels. The concentration of zinc in the first reaction gas and the concentration of oxygen in the second reaction gas may be transitioned in an alternating sequence, so that relatively high zinc concentrations in the first reaction gas overlap with relatively low oxygen concentrations in the second reaction gas and vice versa.

Claims

1. A method of forming a p-type ZnO-based II-VI compound semiconductor layer, comprising:

depositing at least first and second p-type ZnO-based II-VI compound semiconductor layers on a substrate at a first temperature in a first range from about 200°

C. to about 600°

C. and at a different second temperature in a second range from about 400°

C. to about 900°

C., respectively.

2. The method of claim 1, wherein said depositing comprises depositing the second p-type ZnO-based II-VI compound semiconductor layer on the first p-type ZnO-based II-VI compound semiconductor layer or vice versa.

3. The method of claim 2, wherein said depositing comprises exposing the substrate to a combination of a first reaction gas containing zinc, a second reaction gas containing oxygen and a p-type dopant gas containing at least one p-type dopant species selected from a group consisting of silver, potassium and gold.

4. The method of claim 3, wherein a concentration of the at least one p-type dopant species in the p-type dopant gas is repeatedly transitioned between at least two different concentration levels while a temperature of the substrate is being transitioned between at least two different temperatures.

5. The method of claim 3, wherein a concentration of the at least one p-type dopant species in the p-type dopant gas is repeatedly transitioned between at least two different concentration levels while a temperature of the substrate is being transitioned between the first and second different temperatures.

6. A method of forming a p-type ZnO-based II-VI compound semiconductor layer, comprising:

providing a substrate; and

depositing a p-type ZnO-based II-VI compound semiconductor layer on the substrate using vapor phase epitaxy,

wherein the p-type ZnO-based II-VI compound semiconductor layer includes at least one p-type dopant species selected from a group consisting of silver, potassium and gold, and

wherein depositing the p-type ZnO-based II-VI compound semiconductor layer includes nucleating ZnO-based II-VI compound semiconductor crystals on the substrate.

7. The method of claim 6, wherein depositing the p-type ZnO-based II-VI compound semiconductor layer is performed using metal organic vapor phase epitaxy.

8. The method of claim 6, further comprising densifying the p-type ZnO-based II-VI compound crystals.

9. The method of claim 6, wherein the at least one p-type dopant species is incorporated in-situ during vapor phase epitaxy.

10. The method of claim 6, wherein nucleating the ZnO-based II-VI compound semiconductor crystals is performed at a temperature of about 400°

C.

11. A method of forming a ZnO-based II-VI compound semiconductor layer, comprising:

depositing at least first and second ZnO-based II-VI compound semiconductor layers on a substrate at a first temperature in a first range from about 200°

C. to about 600°

C. and at a different second temperature in a second range from about 400°

C. to about 900°

C., respectively, said at least first and second ZnO-based II-VI compound semiconductor layers including at least one p-type ZnO-based II-VI compound semiconductor layer.