Doping method and method of manufacturing field effect transistor

A doping method comprising the steps of:

• obtaining a proportion X of ions of a compound including a donor impurity or an acceptor impurity in total ions from mass spectrum by generating plasma using a first source gas in which the compound including the donor impurity or the acceptor impurity is diluted with a diluent gas made of hydrogen or a rare gas to a first concentration of 5% to 40% in an ion doping apparatus;
• and
• analyzing a peak concentration Y of the compound including the donor impurity or the acceptor impurity in a first processing object which is doped with ions of the compound including the donor impurity or the acceptor impurity by the ion doping apparatus using a second source gas in which the compound including the donor impurity or the acceptor impurity is diluted with the diluent gas to a second concentration lower than the first concentration, referring a dose amount of total ions to be D0 and setting an acceleration voltage at a value,
• obtaining a dose amount D1 of total ions from a first relational expression, Y=(D1/D0)(aX +b), and from a second relational expression, Vth=cY1/2+d, wherein a, b, c and d are assumed to be real numbers, and
• doping a second processing object with the donor impurity or the acceptor impurity by the ion doping apparatus using a third source gas, wherein a dose amount of total ions is set at D1, and an acceleration voltage is set at the value, and
• wherein Vth is a threshold voltage of a field effect transistor manufactured by using the second processing object which is doped with the donor impurity or the acceptor impurity.

A manufacturing method of a field effect transistor comprising the steps of:

• obtaining a proportion X (0<X<1) of ions of a compound including a donor impurity or an acceptor impurity in total ions from mass spectrum by generating plasma using a first source gas in which the compound including the donor impurity or the acceptor impurity is diluted with a diluent gas made of hydrogen or a rare gas to a first concentration of 5% to 40% in an ion doping apparatus,
• analyzing a peak concentration Y of the compound including the donor impurity or the acceptor impurity in a first processing object which is doped with the ions of the compound including the donor impurity or the acceptor impurity by the ion doping apparatus using a second source gas in which the compound including the donor impurity or the acceptor impurity is diluted with the diluent gas to a second concentration lower than the first concentration, referring to a dose amount of total ions as D0 and setting an acceleration voltage at a value,
• obtaining a dose amount D1 of total ions from a relational expression, Y=(D1/D0)(aX+b), wherein a and b are assumed to be real numbers, and
• doping a second processing object with the donor impurity or the acceptor impurity by the ion doping apparatus using a third source gas, wherein a dose amount of total ions is set at D1, and an acceleration voltage is set at the value.

A manufacturing method of a field effect transistor comprising the steps of:

• obtaining a proportion X of ions of a compound including a donor impurity or an acceptor impurity in total ions from mass spectrum by generating plasma using a first source gas in which the compound including the donor impurity or the acceptor impurity is diluted with a diluent gas made of hydrogen or a rare gas to a first concentration of 5% to 40% in an ion doping apparatus;
• and
• analyzing a peak concentration Y of the compound including the donor impurity or the acceptor impurity in a first processing object which is doped with ions of the compound including the donor impurity or the acceptor impurity by the ion doping apparatus using a second source gas in which the compound including the donor impurity or the acceptor impurity is diluted with the diluent gas to a second concentration lower than the first concentration, referring a dose amount of total ions to be D0 and setting an acceleration voltage at a value,
• obtaining a dose amount D1 of total ions from a first relational expression, Y=(D1/D0)(aX+b), and from a second relational expression, Vth =cY1/2+d, wherein a, b, c and d are assumed to be real numbers, and
• doping a second processing object with the donor impurity or the acceptor impurity by the ion doping apparatus using a third source gas, wherein a dose amount of total ions is set at D1, and an acceleration voltage is set at the value, and
• wherein Vth is a threshold voltage of the field effect transistor manufactured by using the second processing object which is doped with the donor impurity or the acceptor impurity.