%A Wang Shou-Guo (王守国), Zhang Yi-Men (张义门), Zhang Yu-Ming (张玉明) %T Theoretical investigation of incomplete ionization of dopants in uniform and ion-implanted 4H-SiC MESFETs %0 Journal Article %D 2003 %J Chin. Phys. B %R 10.1088/1009-1963/12/1/316 %P 89-93 %V 12 %N 1 %U {https://cpb.iphy.ac.cn/CN/abstract/article_107150.shtml} %8 2003-01-20 %X The effects of incomplete ionization of nitrogen in 4H-SiC have been investigated. Poisson's equation is numerically analysed by considering the effects of Poole--Frenkel, and the effects of the potential on $N^+_{\rm d}$ (the concentration of ionized donors) and $n$ (the concentration of electrons). The pinch-off voltages of the uniform and the ion-implanted channels of 4H-SiC metal-semiconductor field-effect transistors (MESFETs) and the capacitance of the gate are given at different temperatures. Both the Poole--Frenkel effect and the potential have influence on the pinch-off voltage $V_{\rm p}$ of 4H-SiC MESFETs. Although the $C$-$V$ characteristics of the ion-implanted and the uniform channel of 4H-SiC MESFETs have a clear distinction, the effects of incomplete ionization on the $C$-$V$ characteristics are not significant.