Method of making thin film transistor with offset drain

A method of forming a thin film transistor of a first conductivity type comprising the following steps:

• providing a thin film transistor layer of semiconductive material;
• first masking the thin film transistor layer to mask a drain offset region while leaving a channel region exposed;
• with the first masking in place, doping the exposed channel region with a conductivity enhancing impurity, the channel region doping being conducted to provide second conductivity type impurity in the channel region to a first concentration;
• second masking the thin film transistor layer to mask the channel region and the drain offset region and leave opposing source/drain regions exposed;
• and
• subjecting the drain offset region to second conductivity type doping to a second concentration, the second concentration being less than the first concentration;
• the thin film transistor layer is void of any blanket doping;
• and
• with the second masking in place, doping the exposed source/drain regions with a conductivity enhancing impurity of the first conductivity type.

A method of forming a thin film transistor of a first conductivity type comprising the following sequential steps:

• forming a thin film transistor layer of semiconductive material;
• blanket doping the thin film transistor layer with a conductivity enhancing impurity of a second conductivity type to a first concentration;
• first masking the thin film transistor layer to mask a drain offset region while leaving a channel region exposed;
• with the first masking in place, doping the exposed channel region with a conductivity enhancing impurity to a second concentration, the second concentration being less than the first;
• second masking the thin film transistor layer to mask the channel region and the drain offset region and leave opposing source/drain regions exposed;
• and
• with the second masking in place, doping the exposed source/drain regions with a conductivity enhancing impurity of the first conductivity type.

A method of forming a thin film transistor of a first conductivity type comprising the following steps:

• providing a thin film transistor layer of semiconductive material;
• doping a drain offset region of the thin film transistor layer with a second conductivity type impurity;
• first masking the thin film transistor layer to mask only the drain offset region of the thin film transistor layer while leaving the source and channel exposed;
• with the first masking in place, doping the exposed channel region with a conductivity enhancing impurity;
• second masking the thin film transistor layer to mask the channel region and the drain offset region and leave opposing source/drain regions exposed;
• and
• with the second masking in place, doping the exposed source/drain regions with a conductivity enhancing impurity of the first conductivity type.

A method of forming a thin film transistor of a first conductivity type comprising the following steps:

• providing a thin film transistor layer of semiconductive material;
• doping a drain offset region of the thin film transistor layer with a conductivity enhancing impurity of the second conductivity type to a first concentration;
• and
• first masking the thin film transistor layer to mask only the drain offset region of the thin film transistor layer while leaving the source and channel exposed;
• with the first masking in place, doping the exposed channel region with a conductivity enhancing impurity of a second conductivity type to provide second conductivity type impurity in the channel region to a second concentration, the second concentration being greater than the first concentration;
• second masking the thin film transistor layer to mask the channel region and the drain offset region and leave opposing source/drain regions exposed;
• and
• with the second masking in place, doping the exposed source/drain regions with a conductivity enhancing impurity of the first conductivity type.