Abstract:
To furnish an IGFET (120 or 122) with an asymmetrically doped channel zone (144 or 164), a mask (212) is provided over a semiconductor body and an overlying electrically insulated gate electrode (148P or 168P). Ions of a semiconductor dopant species are directed toward an opening (213) in the mask from two different angular orientations along paths that originate laterally beyond opposite respective opening-defined sides of the mask. The location and shape of the opening are controlled so that largely only ions impinging from one of the angular orientations enter the intended location for the channel zone. Ions impinging from the other angular orientation are shadowed by the mask from entering the channel zone location. Although the ions impinging from this other angular orientation do not significantly dope the channel zone location, they normally enter the semiconductor body elsewhere, e.g., the intended location for the channel zone of another IGFET.
Abstract:
An asymmetric insulated-gate field-effect transistor is configured in an asymmetric lightly doped drain structure that alleviates hot-carrier effects and enables the source characteristics to be decoupled from the drain characteristics. The transistor has a multi-part channel formed with an output portion, which adjoins the drain zone, and a more heavily doped input portion, which adjoins the source zone. The drain zone contains a main portion and more lightly doped extension that meets the output channel portion. The drain extension extends at least as far below the upper semiconductor surface as the main drain portion so as to help reduce hot-carrier effects. The input channel portion is situated in a threshold body zone whose doping determines the threshold voltage. Importantly, the provision of a lightly doped source extension is avoided so that improving the drain characteristics does not harm the source characteristics, and vice versa. In fabricating complementary versions of the transistor, the threshold body zone of one transistor can be formed at the same time as the drain extension of a complementary transistor, and vice versa.
Abstract:
A structure containing multiple field-effect transistors (60 and 150) is fabricated from a semiconductor body having material (82) of a specified conductivity type. Semiconductor dopant of the specified conductivity type is introduced, typically simultaneously, (a) into part of a first channel zone of the material of the specified conductivity type to define a threshold channel portion (66) more heavily doped than a main channel portion (65) and (b) into substantially all of a second channel zone of the material of the specified conductivity type. First and second gate electrodes (69 and 141) are provided respectively above, and insulatingly spaced apart from, the first and second channel zones. Semiconductor dopant of the opposit conductivity type is introduced into the semiconductor body to define (a) a pair of first source/drain zones (63/64 and 75/76) laterally separated by the first channel zone and (b) a pair of second source/drain zones (133/134 and 135/136) laterally separated by the second channel zone.
Abstract:
A pair of complementary CJIGFETs (100 and 160) are created from a body of semiconductor material (102 and 104). Each CJIGFET is formed with (a) a pair of laterally separated source/drain zones (112 and 114 or 172 and 174) situated along the upper surface of the semiconductor body, (b) a channel region (110 or 170) extending between the source/drain zones, and (c) a gate electrode (118 or 178) overlying, and electrically insulated from, the channel region. The gate electrode of each CJIGFET has a Fermi energy level within 0.3 ev of the middle of the energy band gap of the semiconductor material. One of the transistors typically conducts current according to a field-induced-channel mode while the other transistor conducts current according to a metallurgical-channel mode. The magnitude of the threshold voltage for each CJIGFET is normally no more than 0.5 V.
Abstract translation:由半导体材料体(102和104)产生一对互补CJIGFET(100和160)。 每个CJIGFET形成有(a)沿着半导体主体的上表面定位的一对横向分离的源极/漏极区(112和114或172和174),(b)沟槽区(110或170) 源极/漏极区,和(c)覆盖并且与沟道区电绝缘的栅电极(118或178)。 每个CJIGFET的栅电极在半导体材料的能带隙的中间具有0.3ev以内的费米能级。 一个晶体管通常根据场致感沟道模式导通电流,而另一晶体管根据冶金通道模式导通电流。 每个CJIGFET的阈值电压幅值通常不超过0.5 V.
Abstract:
Each of a pair of complementary insulated-gate field-effect transistors is manufactured in an asymmetric lightly doped drain structure that enables the source characteristics to be decoupled from the drain characteristics. Each transistor has a multi-part channel formed with an output portion, which adjoins the drain zone, and a more heavily doped input portion, which adjoins the source zone. The drain zone of each transistor contains a main portion and a more lightly doped extension that meets the output channel portion. The drain extension of each transistor typically extends at least as far below the upper semiconductor surface as the main drain portion so as to help reduce hot-carrier effects. The input channel portion of each transistor is situated in a threshold body zone whose doping determines the threshold voltage. Importantly, the provision of lightly doped source extensions is avoided so that improving the drain characteristics does not harm the source characteristics, and vice versa. In fabricating the complementary transistor structure, the threshold body zone of each transistor is formed at the same time as the drain extension of the other transistor.
Abstract:
Parts of the emitter and base of a vertical bipolar transistor adjoin a field-isolation region to form a walled-emitter structure. The transistor is furnished with extra doping in the collector and, optionally, in the base. The extra collector doping is provided along collector-base junction below the intrinsic base to create a special collector zone spaced laterally apart from the field-isolation region. The presence of the special collector zone causes the intrinsic base to be thinner, thereby raising the cutoff frequency and overall current gain. The extra base doping is provided in the intrinsic base along the field-isolation region to improve the transistor's breakdown voltage and leakage current characteristics.
Abstract:
A special two-dimensional intrinsic base doping profile is utilized to improve the output current-voltage characteristics of a vertical bipolar transistor whose intrinsic base includes a main intrinsic portion. The special doping profile is achieved with a pair of more lightly doped base portions that encroach substantially into the intrinsic base below the main intrinsic base portion. The two deep encroaching base portions extend sufficiently close to each other to set up a two-dimensional charge-sharing mechanism that typically raises the magnitude of the punch-through voltage. The transistor's current-voltage characteristics are thereby enhanced. Manufacture of the transistor entails introducing suitable dopants into a semiconductor body. In one fabrication process, a fast-diffusing dopant is employed in forming the deep encroaching base portions without significantly affecting earlier-created transistor regions.
Abstract:
Parts of the emitter and base of a vertical bipolar transistor adjoin a field-isolation region to form a walled-emitter structure. The transistor is furnished with extra doping in the collector and, optionally, in the base. The extra collector doping is provided along collector-base junction below the intrinsic base to create a special collector zone spaced laterally apart from the field-isolation region. The presence of the special collector zone causes the intrinsic base to be thinner, thereby raising the cutoff frequency and overall current gain. The extra base doping is provided in the intrinsic base along the field-isolation region to improve the transistor's breakdown voltage and leakage current characteristics.
Abstract:
A special two-dimensional intrinsic base doping profile is utilized to improve the output current-voltage characteristics of a vertical bipolar transistor whose intrinsic base includes a main intrinsic portion. The special doping profile is achieved with a pair of more lightly doped base portions that encroach substantially into the intrinsic base below the main intrinsic base portion. The two deep encroaching base portions extend sufficiently close to each other to set up a two-dimensional charge-sharing mechanism that typically raises the magnitude of the punch-through voltage. The transistor's current-voltage characteristics are thereby enhanced.
Abstract:
Two topologically different cells are disclosed that reduce the total number of contacts per device and that are applicable to mid- to high-voltage DMOS transistors. These cells use integrated connections between the source and the body that make them less sensitive to contact obturations by particle contamination or lithography imperfections. The topologies include either an elongated hexagonal cell or a buried-deep-body cell. Both cells are most efficient in high-current medium-voltage trench DMOS transistors, where the density of body contacts becomes prohibitive while the perimeter/area geometry factor is less critical. The disclosed embodiments are of the trench type of DMOS construction. The cells may, however, be implemented in planar DMOS transistors as well.