Polarization doping: Reservoir effects of the substrate in AlGaN graded layers

High electron sheet concentrations of ∼1015 cm−2 result from polarization doping with compositionally graded AlGaN films grown on unintentionally doped GaN templates which exhibit background electron concentrations of ∼1016 cm−3. Similar graded films grown on semi-insulating (SI), free standing GaN substrates exhibited carrier concentrations two orders less. Transport studies of the as-grown materials using temperature dependent Hall effect revealed a very weak temperature dependence of the carrier concentration and mobility as compared to traditionally doped films using Si as a dopant. And qualitative modeling of the electron mobility indicates that alloy scattering and charged dislocation scattering are the most significant contributors to limiting the mobility over the entire temperature range.

[1]  G. Salamo,et al.  Isotropic Hall effect and ''freeze-in'' of carriers in the InGaAs self-assembled quantum wires , 2011 .

[2]  Shu-Hsuan Chang,et al.  Numerical investigation on the enhanced carrier collection efficiency of Ga-face GaN/InGaN p-i-n solar cells with polarization compensation interlayers. , 2011, Optics letters.

[3]  Eric Feltin,et al.  Self heating in AlInN/AlN/GaN high power devices: Origin and impact on contact breakdown and IV characteristics , 2011 .

[4]  G. Salamo,et al.  Polarization induced doping in graded AlGaN films , 2011 .

[5]  Liu Lu,et al.  Characterization of the gate oxide of an AlGaN/GaN high electron mobility transistor , 2011 .

[6]  Yong Zeng,et al.  Theoretical study of polarization-doped GaN-based light-emitting diodes , 2011 .

[7]  Junxi Wang,et al.  Three-dimensional hole gas induced by polarization in (0001)-oriented metal-face III-nitride structure , 2010 .

[8]  Debdeep Jena,et al.  Polarization-Induced Hole Doping in Wide–Band-Gap Uniaxial Semiconductor Heterostructures , 2010, Science.

[9]  Hongxing Jiang,et al.  Si-Doped High Al-Content AlGaN Epilayers with Improved Quality and Conductivity Using Indium as a Surfactant , 2008 .

[10]  D. Jena,et al.  Carrier transport and confinement in polarization-induced three-dimensional electron slabs: Importance of alloy scattering in AlGaN , 2006 .

[11]  S. Denbaars,et al.  Electron mobility in graded AlGaN alloys , 2006 .

[12]  D. Look,et al.  Identification of Donors, Acceptors, and Traps in Bulk-Like HVPE GaN , 2005 .

[13]  O. Ambacher,et al.  Magnetotransport properties of a polarization-doped three-dimensional electron slab in graded AlGaN , 2002, cond-mat/0209664.

[14]  S. Denbaars,et al.  Realization of wide electron slabs by polarization bulk doping in graded III–V nitride semiconductor alloys , 2002, cond-mat/0204487.

[15]  D. Look,et al.  High mobility in n-type GaN substrates , 2001 .

[16]  Oliver Ambacher,et al.  Role of Spontaneous and Piezoelectric Polarization Induced Effects in Group-III Nitride Based Heterostructures and Devices , 1999 .

[17]  David C. Look,et al.  Dislocation Scattering in GaN , 1999 .

[18]  B. Ridley Exact electron momentum-relaxation times in GaN associated with scattering by polar-optical phonons , 1998 .

[19]  David C. Look,et al.  Degenerate layer at GaN/sapphire interface: Influence on Hall-effect measurements , 1997 .

[20]  S. Denbaars,et al.  Accurate mobility and carrier concentration analysis for GaN , 1997 .

[21]  H. K. Ng,et al.  Magneto‐optical studies of GaN and GaN/AlxGa1−xN: Donor Zeeman spectroscopy and two dimensional electron gas cyclotron resonance , 1996 .

[22]  G. E. Stillman,et al.  Electrical characterization of epitaxial layers , 1976 .