Browse Prior Art Database

Dumbbell Resistor Test Structure

IP.com Disclosure Number: IPCOM000077799D
Original Publication Date: 1972-Sep-01
Included in the Prior Art Database: 2005-Feb-25
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Magdo, I: AUTHOR [+2]

Abstract

Dumbbell resistor test structures, which are broadly covered in U.S. Patents 3,335,34O and 3,465,427, are used for in-line testing of transistor base parameters during the fabrication of integrated circuits.

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 74% of the total text.

Page 1 of 2

Dumbbell Resistor Test Structure

Dumbbell resistor test structures, which are broadly covered in U.S. Patents 3,335,34O and 3,465,427, are used for in-line testing of transistor base parameters during the fabrication of integrated circuits.

With the ever-increasing densities of devices and integrated circuits and the attendant decrease in dimensions of such devices, the present dumbbell resistor test structure provides a test device which, as closely as possible, simulates the structure and parameters of the intrinsic base region of a typical transistor in the integrated circuit.

With reference to Figs. 1 and 2, the dumbbell structure comprises P region 10 which has the same doping level and diffusion depth as an actual transistor base. P region 10 is formed in N-type epitaxial region 11 which is on P-type substrate 12. A buried N+ subcollector region 13 has the doping level of a typical transistor subcollector region and a typical subcollector size, and lies partly under region 10. The expanded dumbbell portions 14 of P region 10 have lateral dimensions many times that of the extrinsic base region in the transistor, for the purpose of making easily accessible test probe contacts through openings 15 to the region with a minimum of contact resistance. However, N+ region 16, which corresponds to the emitter in the device, has lateral dimensions which are substantially identical to that of the actual device emitter. This results in the intrinsic base region in the t...