Oxygen-doped group III metal nitride and method of manufacture
A gallium-containing nitride crystals are disclosed, comprising: a top surface having a crystallographic orientation within about 5 degrees of a plane selected from a (0001) +c-plane and a (000-1) −c-plane; a substantially wurtzite structure; n-type electronic properties; an impurity concentration of hydrogen greater than about 5×10 17 cm −3 ; an impurity concentration of oxygen between about 2×10 17 cm −3 and about 1×10 20 cm −3 ; an [H]/[O] ratio of at least 0.3; an impurity concentration of at least one of Li, Na, K, Rb, Cs, Ca, F, and Cl greater than about 1×10 16 cm −3 ; a compensation ratio between about 1.0 and about 4.0; an absorbance per unit thickness of at least 0.01 cm −1 at wavenumbers of approximately 3175 cm −1 , 3164 cm −1 , and 3150 cm −1 ; and wherein, at wavenumbers between about 3200 cm −1 and about 3400 cm −1 and between about 3075 cm −1 and about 3125 cm −1 , said gallium-containing nitride crystal is essentially free of infrared absorption peaks having an absorbance per unit thickness greater than 10% of the absorbance per unit thickness at 3175 cm.
1. A device, comprising:
a gallium-containing nitride crystal substrate comprising gallium and nitrogen and having a wurtzite structure and comprising a first surface and a second surface opposite the first surface;
at least one n-type epitaxial layer, at least one AlInGaN epitaxial layer, and at least one p-type epitaxial layer overlying at least a portion of the first surface;
a p-contact disposed over at least a portion of the p-type epitaxial layer; and
an n-contact,
wherein the gallium-containing nitride crystal substrate comprises point defects having defect types and relative concentrations resulting in a compensation ratio between about 1.0 and about 4.0, said point defects being characterized by an absorbance per unit thickness of at least 0.01 cm −1 at wavenumbers of approximately 3175 cm −1 , 3164 cm −1 , and 3150 cm −1 and
at wavenumbers between about 3200 cm −1 and about 3400 cm −1 and between about 3075 cm −1 and about 3125 cm −1 , said gallium-containing nitride crystal substrate being essentially free of infrared absorption peaks having an absorbance per unit thickness greater than 10% of the absorbance per unit thickness at 3175 cm −1 .
2. The device of claim 1 , wherein said first surface has a crystallographic orientation within about 5 degrees of a plane selected from a (0001) +c-plane or a (000-1) −c-plane;
n type doping;
an impurity concentration of hydrogen greater than about 5×10 17 cm −3 ;
an impurity concentration of oxygen between about 2×10 17 cm −3 and about 1×10 20 cm −3 ;
an [H]/[O] ratio of at least 0.3; and
an impurity concentration of at least one of Li, Na, K, Rb, Cs, Ca, F, and Cl greater than about 1×10 16 cm −3 .
3. The device of claim 1 , wherein said gallium-containing nitride crystal substrate is characterized by a carrier concentration n between about 3×10 17 cm −3 and about 1×10 20 cm −3 and a carrier mobility η, in units of centimeters squared per volt-second, such that the logarithm to the base 10 of the quantity (1.2×η) is greater than about −0.4115[log10(n)]+10.028.
4. The device of claim 1 , wherein said gallium-containing nitride crystal substrate is characterized by a carrier concentration between about 3×10 17 cm −3 and about 5×10 19 cm −3 .
5. The device of claim 1 , wherein said gallium-containing nitride crystal substrate is characterized by a compensation ratio between about 1.5 and about 3.5.
6. The device of claim 2 , wherein the [H]/[O] ratio is between about 0.5 and about 1.3.
7. The device of claim 1 , wherein said gallium-containing nitride crystal substrate is characterized by a cathodoluminescence peak at about 423 nm.
8. The device of claim 1 , wherein said gallium-containing nitride crystal substrate is further characterized by a cathodoluminescence peak at about 550 nm.
9. The device of claim 1 , wherein
the point defects are further characterized by an absorbance per unit thickness of at least 0.01 cm −1 at a wavenumber of approximately 3188 cm −1 , wherein the absorbance per unit thickness at 3188 cm −1 has a value between 5% and 25% of that of the absorbance per unit thickness at 3175 cm −1 .
10. The device of claim 1 , wherein
said point defects are further characterized by an absorbance per unit thickness at wavenumbers from about 3188 cm −1 to about 3400 cm −1 that is less than 25% of that of the absorbance per unit thickness at 3175 cm −1 .
11. A device, comprising:
a gallium-containing nitride crystal substrate comprising gallium and nitrogen and having a wurtzite structure, comprising an n-type dopant, and further comprising a first surface and a second surface opposite the first surface;
at least one n-type epitaxial layer, at least one AlInGaN epitaxial layer, and at least one p-type epitaxial layer overlying at least a portion of the first surface;
a p-contact disposed over at least a portion of the p-type epitaxial layer; and
an n-contact,
wherein the gallium-containing nitride crystal substrate comprises:
impurities of hydrogen [H] and oxygen [O], wherein a ratio of an impurity concentration of hydrogen [H] to an impurity concentration of oxygen [O] is at least 0.3; and
impurities of at least one of Li, Na, K, Rb, Cs, Ca, F, and Cl having an impurity concentration of greater than about 1×10 16 cm −3 , wherein
a ratio of the impurity concentration of oxygen to an n-type carrier concentration n is between 1.0 and 4.0, and
at wavenumbers between about 3200 cm −1 and about 3400 cm −1 , said gallium-containing nitride crystal substrate is essentially free of infrared absorption peaks having an absorbance per unit thickness greater than 0.01 cm −1 , as measured by Fourier transform infrared spectrometry (FTIR).
12. The device of claim 11 , wherein at wavenumbers between about 3075 cm −1 and about 3125 cm −1 , said gallium-containing nitride crystal substrate is essentially free of infrared absorption peaks having an absorbance per unit thickness greater than 0.01 cm −1 , as measured by Fourier transform infrared spectrometry.
13. The device of claim 11 , wherein the gallium-containing nitride crystal substrate further comprises defects that are characterized by an absorbance per unit thickness of at least 0.01 cm −1 at wavenumbers of approximately 3175 cm −1 , 3164 cm −1 , and 3150 cm −1 , as measured by Fourier transform infrared spectrometry.
14. The device of claim 11 , wherein the gallium-containing nitride crystal substrate is characterized by an n-type carrier concentration n between about 3×10 17 cm −3 and about 1×10 20 cm −3 and by a carrier mobility η, in units of centimeters squared per volt-second, such that a logarithm to the base 10 of a quantity (1.2×η) is greater than about −0.4115[log 10 (n)]+10.028.
15. The device of claim 11 , wherein the gallium-containing nitride crystal substrate is characterized by an n-type carrier concentration n between about 3×10 17 cm −3 and about 5×10 19 cm −3 .
16. The device of claim 11 , wherein the gallium-containing nitride crystal substrate is characterized by a ratio of the impurity concentration of oxygen to the n-type carrier concentration n between about 1.5 and about 3.5.
17. The device of claim 1 , wherein the gallium-containing nitride crystal substrate is characterized by a ratio of the impurity concentration of hydrogen to the impurity concentration of oxygen of between about 0.5 and about 1.3.
18. The device of claim 11 , wherein the gallium-containing nitride crystal substrate is characterized by:
an impurity concentration of hydrogen [H] greater than about 5×10 17 cm −3 ,
an impurity concentration of oxygen [O] between about 2×10 17 cm −3 and about 1×10 20 cm −3 , wherein
the impurity concentrations are measured using calibrated secondary ion mass spectrometry (SIMS).
19. The device of claim 11 , characterized by a cathodoluminescence peak at about 423 nm.
20. The device of claim 19 , further characterized by a cathodoluminescence peak at about 550 nm.