P-TYPE ZINC OXIDE THIN FILM AND METHOD FOR FORMING THE SAME

• US 20090302314A1
• Filed: 07/06/2007
• Published: 12/10/2009
• Est. Priority Date: 07/06/2006
• Status: Abandoned Application

• Current Assignee: National Institute of Advanced Industrial Science and Technology (Government of Japan)
• Original Assignee: National Institute of Advanced Industrial Science and Technology (Government of Japan)
• Inventors: Hori, Takahiro, Kusumori, Takeshi
• Application Number:
  US12/306,336
• Publication Number:
  US 20090302314A1
• Time in Patent Office: Days
• US Class Current: 257/43
• CPC Class Codes: C23C 14/086 of zinc, germanium, cadmium, indium, tin, thallium or bismuth
• CPC Class Codes: C23C 14/28 by wave energy or particle radiation C23C14/32 - C23C14/48 take precedence
• CPC Class Codes: C23C 14/5806 Thermal treatment
• CPC Class Codes: C30B 23/066 Heating of the material to be evaporated
• CPC Class Codes: C30B 29/16 Oxides
• CPC Class Codes: C30B 31/20 Doping by irradiation with electromagnetic waves or by particle radiation
• CPC Class Codes: C30B 33/02 Heat treatment C30B33/04, C30B33/06 take precedence
• CPC Class Codes: H01L 33/0083 for devices with an active region comprising only II-VI compounds

Abstract

The present invention provides a p-type zinc oxide thin film that is clearly shown to be a p-type semiconductor based on the magnetic field dependence of the Hall voltage in the measurement of the Hall effect using a Hall bar, as well as a method for producing such a thin film with good reproducibility, and a light-emitting element thereof, and the present invention relates to the method for producing a p-type zinc oxide semiconductor thin film, for which combination is effected between a high temperature annealing step for activating a p-type dopant added to a zinc oxide thin film in order to develop the p-type semiconductor properties of zinc oxide or irradiating the thin film with an active species of p-type dopant to dope the film while the p-type dopant is active, and a low temperature annealing step in an oxidizing atmosphere, whereby conversion to a p-type semiconductor is realized, and relates to a p-type zinc oxide thin film thus produced using this method and a light-emitting element thereof, the present invention thereby affording a highly reliable p-type zinc oxide thin film, method of producing the same, and blue light-emitting element thereof.

Claims

1. A p-type zinc oxide semiconductor thin film, characterized in that 1) a p-type dopant added to the thin film is in an activated state, 2) excess zinc is removed, 3) the inclination in a graph of Hall voltage-magnetic field properties in results for Hall effect measurements clearly reveals the film to be a p-type semiconductor, and 4) whereby conversion to a p-type semiconductor is realized.

2. The p-type zinc oxide semiconductor thin film according to claim 1, characterized in that the magnetic field dependence of the Hall voltage in measurement of the Hall effect using a Hall bar clearly reveals that the film is a p-type semiconductor.

3. The p-type zinc oxide semiconductor thin film according to claim 1, comprising a substrate, the p-type zinc oxide semiconductor thin film being characterized in that the substrate is a glass substrate, sapphire substrate, zinc oxide monocrystalline substrate, or a substrate having a zinc oxide monocrystalline thin film on a surface layer thereof, regardless of crystal symmetry or compatibility of lattice constant with the p-type zinc oxide thin film to be formed thereon.

4. The p-type zinc oxide semiconductor according to claim 1, characterized in that the zinc oxide thin film converted to a p-type is a monocrystalline (epitaxial) thin film or polycrystalline thin film.

5. The p-type zinc oxide semiconductor thin film according to claim 1, characterized in that the Hall concentration is at least 1×

10¹⁵ cm<sup>−

3</sup>.

6. The p-type zinc oxide semiconductor thin film according to claim 1, characterized in that the electrical resistivity is not more than 100 Ω

·

cm.

12. A light-emitting element, comprising a structure in which the p-type zinc oxide thin film according to any of claims 1 to 6 is formed on a substrate.

13. The light-emitting element according to claim 12, comprising a structure in which a monocrystalline (epitaxial) thin film or polycrystalline thin film is formed on a glass substrate, sapphire substrate, zinc oxide monocrystalline substrate, or a substrate having a zinc oxide crystalline thin film on a surface thereof.

7. A method for producing a p-type zinc oxide semiconductor thin film, characterized by combining a step for activating a p-type dopant added to a zinc oxide thin film in order to develop p-type semiconductor properties of zinc oxide, and a step for low temperature annealing in an oxidizing atmosphere, whereby conversion to a p-type semiconductor is realized.

8. The method for producing a p-type zinc oxide semiconductor thin film according to claim 7, characterized in that the thin film is annealed at a high temperature of 700 to 1200°

C. in an inert gas atmosphere or nitrogen gas atmosphere as the step for activating the p-type dopant added to the zinc oxide thin film.

9. The method for producing a p-type zinc oxide semiconductor thin film according to claim 7, characterized in that the substrate surface is irradiated with an active species of dopant so that the thin film is doped while the p-type dopant is activated during the step of growing the zinc oxide thin film as the step for activating the p-type dopant added to the zinc oxide thin film.

10. The method for producing a p-type zinc oxide semiconductor thin film according to claim 7, characterized in that the thin film is annealed at a low temperature of 200 to 700°

C. in an oxidizing atmosphere as the low temperature annealing step.

11. The method for producing a p-type zinc oxide semiconductor thin film according to claim 7, characterized in that nitrogen is used as the p-type dopant for converting the zinc oxide to a p-type, and this is added either alone or with another element.