2001 Fiscal Year Final Research Report Summary
Study on Impurity Co-Doping by Atomic Positional Control
| Project/Area Number |
11450016
|
|---|
| Research Category |
Grant-in-Aid for Scientific Research (B)
|
| Allocation Type | Single-year Grants |
|---|
| Section | 一般 |
|---|
| Research Field |
Applied materials science/Crystal engineering
|
|---|
| Research Institution | RIKEN (The Institute of Physical & Chemical Research) |
|---|
Principal Investigator |
IWAI Souhachi RIKEN, Semiconductors Lab., Senior Research Scientist, 半導体工学研究室, 先任研究員 (40087474)
|
|---|
| Co-Investigator(Kenkyū-buntansha) |
NOMURA Shintarou University of Tsukuba, Associated Professor, 物理学系, 助教授 (90271527)
AOYAGI Yoshinobu RIKEN, Semiconductors Lab., Chief Scientist, 半導体工学研究室, 先任研究員 (70087469)
HIRAYAMA Hideki RIKEN, Semiconductors Lab., Research Scientist, 半導体工学研究室, 研究員 (70270593)
|
|---|
| Project Period (FY) |
1999 – 2001
|
| Keywords | MOVPE / Gallium Nitride / Aluminum Gallium Nitride / Alternative source supply / Impurity doping / P-type conduction / Hole concentration / Activation energy |
|---|
| Research Abstract |
New impurity doping techniques were developed to obtain highly conductive p-type GaN and Al_xCa_<1-x>N layers by using metal-organic vapor phase epitaxy. Impurity source materials were supplied by controlling the feed time to introduce impurity atoms into specific crystal layers for reducing the acceptor level due to the formation of impurity complexes.
By using alternative feedings of TMG source gas and NH_3 with the feed of Cp_2Mg and TESi during the TMG feed,we obtained a highly hole concentration of 2x10^<19>cm^<-3> for p-type GaN which was grown directly on a low temperature AIN buffer layer on a sapphire substrate.
High quality Al_<0.6>Ga_<0.4>N layers were obtained by alternative supply of TMA/TMG source pulses and NH_3 pulse. Migrations of Al and Ga atoms on the substrate surface were enhanced in the ambience of small amount of NH_3, which suppress the crystal defect due to the desorption of N atoms from the AlGaN surface.
P-type Al_<0.45>Ga_<0.55>N of 4x10^<18>cm^<-3> hole concentration was obtained by Cp_2Mg supply during the feeding time of TMG The temperature dependence of hole concentration yielded 75meV for the activation energy of Mg acceptor, which is about 1/5 as small as that of Mg in AlGaN grown by the continuous feedings of source materials. By feeding the optimum amount of Si source just after the feeding of Mg source, the hole concentration was further increased to 6x10^<18>cm^<-3>, provably due to co-doping effect. This alternative feeding technique with Mg doping was applied to grow a p-type Al_<0.47>Ga_<0.53>N layer in a light emitting diode. U-V emission of 282nm wavelength was observed from the diode by current injection through the p-type Al_<0.47>Ga_<0.53>N layer in the p-n junction.
In conclusion, the doping technique by alternative feeding of source materials is one of the candidate techniques to obtain highly p-type conductivity for wide band gap materials like Al_xGa_<1-x>N.
|
