Bent gate transistor modeling
View Patent ↗A method of characterizing a total width and an overall effective length for a bent gate. The bent gate is divided into logical portions, and each of the logical portions is designated as one of a bent portion, a corner portion, and a straight portion. A corner portion gate width and a corner portion effective length are computed for each of the logical portions designated as a corner portion. Similarly, a bent portion gate width and a bent portion effective length are computed for each of the logical portions designated as a bent portion. Likewise, a straight portion gate width and a straight portion effective length are computed for each of the logical portions designated as a straight portion. The total width of the bent gate is computed from the corner portion gate width, the bent portion gate width, and the straight portion gate width. Similarly, the overall effective length of the bent gate is computed from the corner portion effective length, the bent portion effective length, and the straight portion effective length.
1. A method of characterizing a total width and an overall effective length for a bent gate, comprising the steps of:
dividing the bent gate into logical portions,
designating each of the logical portions as one of a bent portion, a corner portion, and a straight portion,
computing a corner portion gate width and a corner portion effective length for each of the logical portions designated as a corner portion,
computing a bent portion gate width and a bent portion effective length for each of the logical portions designated as a bent portion,
computing a straight portion gate width and a straight portion effective length for of the logical portions designated as a straight portion,
computing the total width of the bent gate from the corner portion gate width, the bent portion gate width, and the straight portion gate width, and
computing the overall effective length of the bent gate from the corner portion effective length, the bent portion effective length, and the straight portion effective length.
2. The method of claim 1 , wherein the step of computing the total width of the bent gate comprises computing the total width by:
total width=Σ(corner portion gate width)+Σ(bent portion gate width)+Σ(straight portion gat e width),
and the step of computing the overall effective length of the bent gate comprises computing the overall effective length by:
effective length=(total width)/(Σ(corner portion gate width)/(corner portion effective length)+Σ(bent portion gate width)/(bent portion effective length)+Σ(straight portion gat e width)/((straight portion effective length)).
3. The method of claim 1 , wherein the step of computing a corner portion gate width and a corner portion effective length for each logical portion designated as a corner portion comprises:
computing the corner portion gate width by
2πR(corner angle)/360, and
computing the corner portion effective length by
L gate /cos((corner angle)/2),
where the corner angle is measured in degrees and L gate is a gate length as measured on a side of the corner portion.
4. The method of claim 1 , wherein the step of computing a bent portion gate width and a bent portion effective length for each logical portion designated as a bent portion comprises:
computing the bent portion gate width by
√2(L jog )−(2R)tan((corner angle/2), and
computing the bent portion effective length by
L gate ,
where the corner angle is measured in degrees and L gate is a gate length as measured through the bent portion, and L jog is an offset measured between ends of the bent portion.
5. The method of claim 1 , wherein the step of computing a straight portion gate width and a straight portion effective length for each logical portion designated as a straight portion comprises:
computing the straight portion gate width by
L str −(2R+L gate )tan((corner angle/2), and
computing the straight portion effective length by
L gate ,
where the corner angle is measured in degrees, L gate is a gate length as measured on a side of the corner portion, and L str is a measure of an average length of the straight portion measured between ends of the straight portion.
6. The method of claim 1 , further comprising the steps of:
computing a critical value for each bent portion and each straight portion,
comparing the critical value for each bent portion and each straight portion to a characteristic value for each bent portion and each straight portion, and
when the characteristic value is not greater than the critical value, then selectively computing the widths and the effective lengths for the bent portions and the straight portions using modified equations.
7. The method of claim 6 , wherein:
the critical value for the bent portion is (2R)tan((corner angle)/2)/√2, and the characteristic value for the bent portion is L jog , where R is a radius of a corner portion at an end of the bent portion, and corner angle is an angle of the corner portion at the end of the bent portion, and L jog is a measured offset between ends of the bent portion, and
the critical value for the straight portion is (2R+L gate )tan((corner angle)/2) and the characteristic value for the straight portion is L str , where L gate is a gate length of the straight portion, and L str is an average width of the straight portion.
8. A method of characterizing a total width for a bent gate, comprising the steps of:
dividing the bent gate into logical portions,
designating each of the logical portions as one of a bent portion, a corner portion, and a straight portion,
computing a corner portion gate width for each of the logical portions designated as a corner portion,
computing a bent portion gate width for each of the logical portions designated as a bent portion,
computing a straight portion gate width for of the logical portions designated as a straight portion, and
computing the total width of the bent gate from the corner portion gate width, the bent portion gate width, and the straight portion gate width.
9. The method of claim 8 , wherein the step of computing the total width of the bent gate comprises computing the total width by total width=Σ(corner portion gate width)+Σ(bent portion gate width)+Σ(straight portion gat e width).
10. The method of claim 8 , wherein the step of computing a corner portion gate width for each logical portion designated as a corner portion comprises 2πR(corner angle)/360, where the corner angle is measured in degrees.
11. The method of claim 8 , wherein the step of computing a bent portion gate width for each logical portion designated as a bent portion comprises √2(L jog )−(2R)tan((corner angle/2), where the corner angle is measured in degrees, and L jog is an offset measured between ends of the bent portion.
12. The method of claim 8 , wherein the step of computing a straight portion gate width for each logical portion designated as a straight portion comprises L str −(2R+L gate )tan((corner angle/2), where the corner angle is measured in degrees, L gate is a gate length as measured on a side of the corner portion, and L str is a measure of an average length of the straight portion measured between ends of the straight portion.
13. The method of claim 8 , further comprising the steps of:
computing a critical value for each bent portion and each straight portion,
comparing the critical value for each bent portion and each straight portion to a characteristic value for each bent portion and each straight portion, and
when the characteristic value is not greater than the critical value, then selectively computing the widths for the bent portions and the straight portions using modified equations.
14. The method of claim 13 ,
the critical value for the bent portion is (2R)tan((corner angle/2)/√2, and the characteristic value far the bent portion is L jog , where R is a radius of a corner portion at an end of the bent portion, and corner angle is an angle of the corner portion at the end of the bent portion, and L jog is a measured offset between ends of the bent portion, and
the critical value for the straight portion is (2R+L gate )tan((corner angle)/2) and the characteristic value for the straight portion is L str , where L gate is a gate length of the straight portion, and L str is an average width of the straight portion.
15. A method of characterizing an overall effective length for a bent gate, comprising the steps of:
dividing the bent gate into logical portions,
designating each of the logical portions as one of a bent portion, a corner portion, and a straight portion,
computing a corner portion effective length for each, of the logical portions designated as a corner portion,
computing a bent portion effective length for each of the logical portions designated as a bent portion,
computing a straight portion effective length for of the logical portions designated as a straight portion, and
computing the overall effective length of the bent gate from the corner portion effective length, the bent portion effective length, and the straight portion effective length.
16. The method of claim 15 , wherein the step of computing the overall effective length of the bent gate comprises computing the overall effective length by effective length=(total width)/(Σ(corner portion gate width)/(corner portion effective length)+Σ(bent portion gate width)/(bent portion effective length)+Σ(straight portion gat e width)/(straight portion effective length)).
17. The method of claim 15 , wherein the step of computing a corner portion effective length for each logical portion designated as a corner portion comprises L gate /cos((corner angle)/2), where the corner angle is measured in degrees and L gate is a gate length as measured on a side of the corner portion.
18. The method of claim 15 , wherein the step of computing a bent portion effective length for each logical portion designated as a bent portion comprises L gate , where L gate is a gate length as measured through the bent portion.
19. The method of claim 15 , wherein the step of computing a straight portion effective length for each logical portion designated as a straight portion comprises L gate , where L gate is a gate length as measured on a side of the corner portion.
20. The method of claim 15 , further comprising the steps of:
computing a critical value for each bent portion and each straight portion,
comparing the critical value for each bent portion and each straight portion to a characteristic value for each bent portion and each straight portion, and
when the characteristic value is not greater than the critical value, then selectively computing the effective lengths for the bent portions and the straight portions using modified equations.