Semiconductor material and method for forming the same and thin film transistor

A thin film transistor comprising:

• a semiconductor layer formed on an insulating surface;
• a channel region formed in said semiconductor layer;
• a gate insulating layer contacting said channel region;
• and
• a gate electrode adjacent to said channel region with said gate insulating layer therebetween,
• wherein said channel region comprises a crystalline silicon semiconductor layer containing oxygen, nitrogen or carbon at a concentration 1.times.10.sup.19 atoms/cm.sup.3 or less and wherein a ratio of a full band width at half maximum (FWHM) of a Raman peak of said channel region to a FWHM of a Raman peak of a single crystalline silicon is less than 3.

A thin film transistor comprising:

• a semiconductor layer formed on an insulating surface;
• a channel region formed in said semiconductor layer;
• a gate insulating layer contacting said channel region;
• and
• a gate electrode adjacent to said channel region with said gate insulating layer therebetween,
• wherein said channel region comprises a crystalline silicon semiconductor layer containing oxygen, nitrogen or carbon at a concentration 1.times.10.sup.9 atoms/cm.sup.3 or less and wherein a peak intensity ratio Ia/Ic of said channel region is less than 0.4 where Ia represents a Raman peak intensity at a wavenumber of 480 cm.sup.-1 for an amorphous component of said channel region and Ic represents a Raman peak intensity at 521 cm.sup.-1 for a single crystalline silicon.

A thin film transistor produced by a process comprising the steps of:

• forming on an insulating surface a semiconductor film having a region to become a channel region of the transistor, said channel region containing therein carbon, nitrogen or oxygen at a concentration of 1.times.10.sup.19 atoms/cm.sup.3 or less, said channel region comprising a material selected from the group consisting of germanium and a germanium silicon alloy;
• and
• irradiating said semiconductor film with a laser beam or a light having a strength equivalent to the laser beam with melting the semiconductor film to increase the degree of crystallinity of at least said channel region, and
• annealing the semiconductor film after the irradiation in a hydrogen atmosphere.

A thin film transistor comprising:

• a semiconductor layer formed on an insulating surface;
• a channel region formed in said semiconductor layer;
• a gate insulating layer contacting said channel region;
• and
• a gate electrode adjacent to said channel region with said gate insulating layer therebetween;
• wherein said channel region comprises a non-single crystalline silicon semiconductor layer containing oxygen, carbon or nitrogen at a concentration 1.times.10.sup.19 atoms/cm.sup.3 or less, which shows a Raman shift at a wavenumber of 512 cm.sup.-1 or higher.

A thin film transistor comprising:

• a semiconductor layer formed on an insulating surface;
• a channel region formed in said semiconductor layer;
• a gate insulating layer contacting said channel region;
• and
• a gate electrode adjacent to said channel region with said gate insulating layer therebetween,
• wherein said channel region comprises a non-single crystalline silicon semiconductor layer containing oxygen, carbon or nitrogen at a concentration 1.times.10.sup.19 atoms/cm.sup.3 or less and wherein a ratio of a full band width at half maximum (FWHM) of a Raman peak of said channel region to a FWHM of a Raman peak of a single crystalline silicon is less than 3.

A thin film transistor comprising:

• a semiconductor layer formed on an insulating surface;
• a channel region formed in said semiconductor layer;
• a gate insulating layer contacting said channel region;
• and
• a gate electrode adjacent to said channel region with said gate insulating layer therebetween,
• wherein said channel region comprises a non-single crystalline silicon semiconductor layer containing oxygen, carbon or nitrogen at a concentration 1.times.10.sup.19 atoms/cm.sup.3 or less and wherein a peak intensity ratio Ia/Ic of said semiconductor layer is less than 0.4 wherein Ia represents a Raman peak intensity at a wavenumber of 480 cm.sup.-1 for an amorphous component of said channel region and Ic represents a Raman peak intensity at 521 cm.sup.-1 for a single crystalline silicon.

A thin film transistor produced by a process comprising the steps of:

• forming on an insulating surface a semiconductor film having a region to become a channel region of the transistor, said channel region containing carbon at a concentration 1.times.10.sup.19 atoms/cm.sup.3 or less and comprising a material selected from the group consisting of germanium and a germanium silicon alloy;
• and
• irradiating the semiconductor film with a laser beam or a light having a strength equivalent to the laser beam to increase the degree of crystallinity of at least said channel region,
• wherein said channel region shows a Raman shift at a wavenumber of 512 cm.sup.-1 or higher.

A thin film transistor produced by a process comprising the steps of:

• forming on an insulating surface a semiconductor film having a region to become a channel region of the transistor, said channel region containing nitrogen at a concentration 1.times.10.sup.19 atoms/cm.sup.3 or less and comprising a material selected from the group consisting of germanium and a germanium silicon alloy;
• and
• irradiating the semiconductor film with a laser beam or a light having a strength equivalent to the laser beam to increase the degree of crystallinity of at least said channel region,
• wherein said channel region shows a Raman shift at a wavenumber of 512 cm.sup.-1 or higher.

A thin film transistor comprising:

• a semiconductor layer formed on an insulating surface;
• a channel region formed in said semiconductor layer;
• a gate insulating layer contacting said channel region;
• and
• a gate electrode adjacent to said channel region with said gate insulating layer therebetween,
• wherein said channel region comprises a material selected from the group consisting of germanium and a germanium silicon alloy, and containing oxygen, nitrogen or carbon at a concentration 1.times.10.sup.19 atoms/cm.sup.3 or less and wherein said channel region shows a Raman shift at a wavenumber of 512 cm.sup.-1 or higher.