PARAMETER EXTRACTION AND 1/F NOISE IN A SURFACE AND A BULK-TYPE, P-CHANNEL LDD MOSFET

P-channel LDD MOSFETs with a p+ -poly gate and an n+ -poly gate are investigated. The p+ -poly gate forms a surface channel and the n+ -poly gate a bulk channel. A new method is proposed to use an L-array for extracting the low field mobility mu00, the mobility degradation coefficient theta, the channel length correction l', and the parameters R(s0) and R(sv) for the gate-voltage-dependent series resistance on the source side R(sS) = R(s0) + R(sv)/V(G)*. A bulk channel device has a higher mu00 value, a lower R(sv) and a smaller series resistance R(Dd) on the drain side than a surface channel device. The theta value and the gate-voltage-independent part of the series resistance R(s0) are about the same in both devices. Under the same external bias conditions, a surface channel MOSFET has a smaller current and a higher l/f current noise than a bulk channel device. The l/f noise parameter alpha is found to be independent of the effective gate voltage and of the channel length for both devices. The bulk channel MOSFET shows alpha values of about 4 x 10(-7) which are among the lowest values ever reported in literature. The alpha values in the surface channel devices are about two orders of magnitude higher than those in the bulk type. Comparing the d.c. characteristics and l/f noise of both devices, an indication is given on how to reduce the l/f noise in a surface p-channel MOSFET.