Low-temperature characterization of buried-channel NMOST

Author

Wilcox, Rick A. ; Chang, Jimmin ; Viswanathan, C.R.

Author_Institution

Dept. of Electr. Eng., California Univ., Los Angeles, CA, USA

Volume

36

Issue

8

fYear

1989

fDate

8/1/1989 12:00:00 AM

Firstpage

1440

Lastpage

1447

Abstract

A comprehensive characterization of buried-channel NMOS transistors at low temperatures down to 30 K is reported. The mobilities of both surface (accumulation) and bulk (buried-channel) electrons were determined as a function of surface electric field and gate bias voltage, respectively, at low temperatures. Both surface electron mobility and buried-channel electron mobility increase with decreasing temperatures. However, a peak in the buried-channel electron mobility is observed around 80 K if the neutral region extends to regions of high impurity concentrations near the surface. A modified MOSCAP (Poisson solver) was used to obtain spatial distributions of carriers and to predict the C-V curves. Low-frequency noise measurements at low temperatures were carried out at gate voltages corresponding to the accumulation, depletion, and inversion modes of operation of the device. In the accumulation mode, a 1/f dependence is observed similar to surface-channel devices. In the depletion mode, a generation-recombination type of noise is observed with a peak around 150 K. In the inversion mode, noise that is related to the hole inversion layer is observed

Keywords

carrier density; carrier mobility; electron device noise; insulated gate field effect transistors; low-temperature techniques; semiconductor device testing; 1/f dependence; 30 to 298 K; C-V curves; MOSCAP; Poisson solver; accumulation mode; buried-channel NMOS transistors; buried-channel electron mobility; depletion mode; gate bias voltage; generation-recombination type; high impurity concentrations; hole inversion layer; inversion mode; low frequence noise; low temperature; spatial carrier distribution; surface electric field; surface electron mobility; Capacitance-voltage characteristics; Charge carriers; Electron mobility; Implants; Low-frequency noise; MOSFETs; Noise measurement; Surface charging; Temperature; Voltage;

fLanguage

English

Journal_Title

Electron Devices, IEEE Transactions on

Publisher

ieee

ISSN

0018-9383

Type

jour

DOI

10.1109/16.30957

Filename

30957