Thermodynamic equilibration of the carbon vacancy in 4H-SiC: A lifetime limiting defect

The carbon vacancy (VC) is a prominent defect in as-grown 4H-SiC epitaxial layers for high power bipolar devices. VC is electrically active with several deep levels in the bandgap, and it is an efficient “killer” of the minority carrier lifetime in n-type layers, limiting device performance. In this study, we provide new insight into the equilibration kinetics of the thermodynamic processes governing the VC concentration and how these processes can be tailored. A slow cooling rate after heat treatment at ∼2000 °C, typically employed to activate dopants in 4H-SiC, is shown to yield a strong reduction of the VC concentration relative to that for a fast rate. Further, post-growth heat treatment of epitaxial layers has been conducted over a wide temperature range (800–1600 °C) under C-rich surface conditions. It is found that the thermodynamic equilibration of VC at 1500 °C requires a duration less than 1 h resulting in a VC concentration of only ∼1011 cm−3, which is, indeed, beneficial for high voltage devic...

[1]  A. Hallén,et al.  Elimination of carbon vacancies in 4H-SiC employing thermodynamic equilibrium conditions at moderate temperatures , 2015 .

[2]  A. Hallén,et al.  Elimination of carbon vacancies in 4H-SiC epi-layers by near-surface ion implantation: Influence of the ion species , 2015 .

[3]  A. Hallén,et al.  Isothermal Treatment Effects on the Carbon Vacancy in 4H Silicon Carbide , 2015 .

[4]  A. Hallén,et al.  Formation of carbon vacancy in 4H silicon carbide during high-temperature processing , 2014 .

[5]  E Janzén,et al.  Negative-U system of carbon vacancy in 4H-SiC. , 2012, Physical review letters.

[6]  B. Svensson,et al.  Oxidation-enhanced annealing of implantation-induced Z(1/2) centers in 4H-SiC: Reaction kinetics and modeling , 2012 .

[7]  T. Kimoto,et al.  Analytical model for reduction of deep levels in SiC by thermal oxidation , 2012 .

[8]  T. Kimoto,et al.  High temperature annealing of n-type 4H-SiC: Impact on intrinsic defects and carrier lifetime , 2012 .

[9]  M. V. Rao,et al.  Microwave Annealing of Very High Dose Aluminum-Implanted 4H-SiC , 2011 .

[10]  Á. Gali,et al.  Large-Scale Electronic Structure Calculations of Vacancies in 4H-SiC Using the Heyd-Scuseria-Ernzerhof Screened Hybrid Density Functional , 2011, 1105.3079.

[11]  B. Svensson,et al.  Enhanced annealing of implantation-induced defects in 4H-SiC by thermal oxidation , 2011 .

[12]  R. Rizzoli,et al.  Carbon-Cap for Ohmic Contacts on Ion-Implanted 4H-SiC , 2010 .

[13]  T. Kimoto,et al.  Elimination of the Major Deep Levels in n- and p-Type 4H-SiC by Two-Step Thermal Treatment , 2009 .

[14]  Tsunenobu Kimoto,et al.  Reduction of Deep Levels and Improvement of Carrier Lifetime in n-Type 4H-SiC by Thermal Oxidation , 2009 .

[15]  P. Klein.  Carrier lifetime measurement in n-4H-SiC epilayers , 2008 .

[16]  H. Tsuchida,et al.  Enhanced annealing of the Z1∕2 defect in 4H–SiC epilayers , 2008 .

[17]  Tsunenobu Kimoto,et al.  Investigation of carrier lifetime in 4H-SiC epilayers and lifetime control by electron irradiation , 2007 .

[18]  Hidekazu Tsuchida,et al.  Reduction of traps and improvement of carrier lifetime in 4H-SiC epilayers by ion implantation , 2007 .

[19]  R. Gutmann,et al.  Effects of annealing on carrier lifetime in 4H-SiC , 2006 .

[20]  B. V. Shanabrook,et al.  Lifetime-limiting defects in n− 4H-SiC epilayers , 2006 .

[21]  Alexander Mattausch,et al.  Ab initio study of the migration of intrinsic defects in 3C-SiC , 2003, cond-mat/0309704.

[22]  C. Jagadish,et al.  Ion mass effect on vacancy-related deep levels in Si induced by ion implantation , 2002 .

[23]  B. Svensson,et al.  Overlapping electron traps in n‐type silicon studied by capacitance transient spectroscopy , 1989 .

[24]  Svensson Bg,et al.  Kinetic study of the 830- and 889-cm-1 infrared bands during annealing of irradiated silicon. , 1986 .

[25]  S. D. Brotherton.  The width of the non-steady state transition region in deep level impurity measurements , 1983 .

[26]  T. Waite,et al.  Theoretical Treatment of the Kinetics of Diffusion-Limited Reactions , 1957 .