Surface roughening in ion implanted 4H-silicon carbide

被引:109
作者
Capano, MA [1 ]
Ryu, S
Cooper, JA
Melloch, MR
Rottner, K
Karlsson, S
Nordell, N
Powell, A
Walker, DE
机构
[1] Purdue Univ, W Lafayette, IN 47907 USA
[2] IMC, Electrum 233, S-16440 Stockholm, Sweden
[3] Epitronics, Danbury, CT USA
[4] USAF, Res Lab, Mat Directorate, Wright Patterson AFB, OH 45433 USA
关键词
annealing ambient; ion implantation; silicon carbide (SiC); surface morphology;
D O I
10.1007/s11664-999-0016-z
中图分类号
TM [电工技术]; TN [电子技术、通信技术];
学科分类号
0808 ; 0809 ;
摘要
Silicon carbide (SiC) devices have the potential to yield new components with functional capabilities that far exceed components based on silicon devices. Selective doping of SiC by ion implantation is an important fabrication technology that-must be completely understood if SiC devices are to achieve their potential. One major problem with ion implantation into SiC is the surface roughening that results from annealing SiC at the high temperatures which are needed to activate implanted acceptor ions, boron or aluminum. This paper examines the causes and possible solutions to surface roughening of implanted and annealed 4H-SiC. Samples consisting of n-type epilayers (5 x 10(15) cm(-3), 4 mu m thick) on 4H-SiC substrates were implanted with B or Al to a total dose of 4 x 10(14) cm(-2) or 2 x 10(15) cm(-2), respectively. Roughness measurements were made using atomic force microscopy. From the variation of root mean square (rms) roughness with annealing temperature, apparent activation energies for roughening following implantation with Al and B were 1.1 and 2.2 eV, respectively, when annealed in argon. Time-dependent activation and surface morphology analyses show a sublinear dependence of implant-activation on time; activation percentages after a 5 min anneal following boron implantation are about a factor of two less than after a 40 min anneal. The rms surface roughness remained relatively constant-with time for anneals in argon at 1750 degrees C. Roughness values at this temperature were approximately 8.0 nm. Annealing experiments performed in different ambients demonstrated the benefits of using silane to maintain good surface morphology. Roughnesses were 1.0 nn (rms) when boron or aluminum implants were annealed in silane at 1100 degrees C, but were about 8 and 11 nm for B and Al, respectively, when annealed in argon at the same temperature.
引用
收藏
页码:214 / 218
页数:5
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