摘要:
A method for making an EEPROM (10) in a semiconductor substrate (40) and EEPROM made according to the method includes forming a gate dielectric (38), such as oxide, nitride, multilayer dielectric, or the like, on a surface of the substrate (40) and forming a polysilicon floating gate (19) on the gate dielectric (38). A control gate (25) is formed at least partially overlying the floating gate (19), and a thermal oxide layer (56) is formed on the floating gate (19) in regions that are not covered by the control gate. Thus, the thermal oxide layer (56) encases any regions of the floating gate (19) uncovered by the control gate (25) and serves as a high quality dielectric to isolate the floating gate (19) from charge loss and other deleterious effects. Then, source and drain regions (21,27) are formed in the substrate (40).
摘要:
A semiconductor device having a p type polysilicon resistor (56) with a moderate sheet resistance and low temperature coefficient of resistance is formed by a double-level polysilicon process. The process also produces n and p-channel transistors (44, 50), a capacitor having upper and lower n type polysilicon capacitor plates (36, 26), an n type polysilicon resistor (32) having a high sheet resistance, and an n type resistor (34) having a low sheet resistance. The p type doping used to form the source/drain regions (48) of p-channel transistor (50) counterdopes n type second level polysilicon to form p type polysilicon resistor (56) without effecting capacitor plates (36, 26) or the n type resistors (32, 34).
摘要:
An integrated circuit having PMOS, NMOS and NPN transistors is described for applications in which both digital and analog circuits are required. The integrated circuit is designed to allow standard CMOS cells to be used in the integrated circuit without redesign. A P+ substrate (48) is provided upon which a first P- epitaxy layer (46) is formed. N+ DUF regions (50,52) are provided for the PMOS and NPN transistors, respectively. The base region (68) is formed in an Nwell (58) by implantation and diffusion. Before diffusion, a nitride layer (70) is formed over the base (68) to provided an inert annealing thereof. The base diffusion and collector diffusion occurs before the CMOS channel stop and source/drain diffusions in order to prevent altering diffusion times for the MOS transistors.
摘要:
A method for fabricating a self-aligned DMOS transistor is provided. The method includes forming a passivation layer (18, 68) on an oxide layer (16, 66) of a substrate (12, 56). The oxide layer (16, 66) is then removed from the surface of the substrate (12, 56) where it is exposed through the passivation layer (18, 68). A reduced surface field region (36, 74) is then formed where the surface of the substrate (12, 56) is exposed through the passivation layer (18, 68). An oxide layer (38, 80) is then formed on the reduced surface field region (36, 74).
摘要:
A semiconductor device having a p type polysilicon resistor (56) with a moderate sheet resistance and low temperature coefficient of resistance is formed by a double-level polysilicon process. The process also produces n and p-channel transistors (44, 50), a capacitor having upper and lower n type polysilicon capacitor plates (36, 26), an n type polysilicon resistor (32) having a high sheet resistance, and an n type resistor (34) having a low sheet resistance. The p type doping used to form the source/drain regions (48) of p-channel transistor (50) counterdopes n type second level polysilicon to form p type polysilicon resistor (56) without effecting capacitor plates (36, 26) or the n type resistors (32, 34).
摘要:
A bipolar transistor is formed on a substrate of a first (P) conductivity type by: forming a collector region (20) of the second conductivity type (N) in the substrate; forming an adjust region (27) of the first (P) conductivity type in the collector region (20); forming a base region (36) of the first (P) conductivity type in the collector region (20), the base region (36) containing the adjust region (27); and forming an emitter region (11) of the second (N) conductivity type in the adjust region (27). The base region (36) is deeper than and more heavily doped than the adjust region (27). The adjust region (27) alters the doping profile of the base-collector junction on the collector (20) side of the junction to increase the breakdown voltage of the transistor.
摘要:
An integrated circuit is provided wherein bipolar, CMOS and DMOS devices are merged together on one chip with fabrication taking place from a CMOS point of view rather than from a bipolar point of view as in the prior art and p-type epitaxial silicon is used as opposed to n-type epitaxial silicon in the prior art. The integrated circuit uses a P+ substrate upon which a P-epitaxial layer is formed. N+ buried regions isolate the DMOS, PMOS and NPN bipolar devices from the P-epitaxial layer. Each of the devices is formed in a N-well with a first level of polysilicon gate layer providing both the gate and masking for the backgate diffusion of the DMOS device and a sidewall oxide later formed on the first level gate layer to control the diffusion of the source and drain regions of the DMOS device to control channel length. A second level of polysilicon layer provides the gate structures for the CMOS devices as well as one plate of a capacitor. The second level of polysilicon acts as a mask for the source and drain region implants of the CMOS devices. A sidewall oxide later formed on the second polysilicon level further controls the channel lengths of the CMOS structures. A third level of polysilicon provides the second capacitor plate for the capacitor. The DMOS device is isolated from the remaining circuitry by the p-type epitaxial layer and the peripheral portion of the DMOS device is terminated by a PN junction.
摘要:
An LDMOS device (10, 20, 50, 60) that is made with minimal feature size fabrication methods, but overcomes potential problems of misaligned Dwells (13). The Dwell (13) is slightly overstated so that its n-type dopant is implanted past the source edge of the gate region (18), which permits the n-type region of the Dwell to diffuse under the gate region (18) an sufficient distance to eliminate misalignment effects.
摘要:
A power field effect transistor is disclosed that includes polysilicon gate bodies (40) and (42), which includes platinum silicide contact layers (74) and (78) disposed on the outer surfaces of bodies (40) and (42), respectively. In addition, the device comprises an n+drain region (64) which also has a platinum silicide drain contact layer (76) formed on its outer surface and platinum silicide source contact layers (75) and (77). During formation, sidewall spacers (50) and (52), as well as mask bodies (70) and (72) are used to ensure that platinum silicide layer (76) spaced apart from both gate bodies (40) and (42) and platinum silicide gate contact layers (74) and (78).
摘要:
A method of manufacturing semiconductor devices with increased operating voltages is described. A dopant of a second conductivity type is implanted into a region of a first epitaxial layer of the first conductivity type to form a buried layer. A substantially smaller dosage of a faster-diffusing dopant of the second conductivity type is then implanted into the buried layer region. The second epitaxial layer of the first conductivity type is formed over the first epitaxial layer. A region of the second epitaxial layer overlying the doped region of the first epitaxial layer is implanted with a dopant of the second conductivity type and diffused to form a doped well. The faster-diffusing dopant diffuses upward to make good electrical contact with the doped well diffusing downward from the surface. The lateral diffusion of the faster-diffusing dopant can be contained, so that lateral spacing design rules do not have to be increased. A thicker second epitaxial layer can thus be used, resulting in increased operating voltage.