HUGHES AIRCRAFT COMPANY v. General Instrument Corp.

374 F. Supp. 1166
CourtDistrict Court, D. Delaware
DecidedApril 23, 1974
DocketCiv. A. 4379
StatusPublished
Cited by4 cases

This text of 374 F. Supp. 1166 (HUGHES AIRCRAFT COMPANY v. General Instrument Corp.) is published on Counsel Stack Legal Research, covering District Court, D. Delaware primary law. Counsel Stack provides free access to over 12 million legal documents including statutes, case law, regulations, and constitutions.

Bluebook
HUGHES AIRCRAFT COMPANY v. General Instrument Corp., 374 F. Supp. 1166 (D. Del. 1974).

Opinion

OPINION

Caleb M. WRIGHT, Senior District Judge.

This is a patent infringement action involving patent No. 3,544,399. The patent in suit discloses a method of making a silicon-gate field effect transistor. The patent was applied for on October 26, 1966 by Hans G. Dill, assignor of the plaintiff and was issued to the plaintiff as assignee on December 1, 1970.

The plaintiff and defendant are both Delaware corporations and this Court has jurisdiction of the subject matter under the provisions of 28 U.S.C. § 1338 and proper venue exists under 28 U.S.C. § 1400(b).

The complaint was filed May 12, 1972. The defendant answered denying infringement and averring that the patent in suit is invalid because the invention of the patent had been “made in this country by another who had not abandoned, suppressed or concealed it” before it was made by the plaintiff’s patentee, Hans Dill. 1 The defendant moved for a stay of the proceedings on the grounds that there was pending in the United States Patent Office the defendant’s application in which the same invention as that in suit was being claimed and that the Patent Office had been asked to declare an interference between the defendant’s application and the patent in suit.

This Court denied the defendant’s motion for a stay of proceedings, ordered discovery be limited for the time being to the issue of priority of invention, and upon the completion of discovery on this issue ordered a separate trial.

THE SUBJECT MATTER OF THE PATENT IN SUIT

The invention is a method of making semiconductor devices of a class known as silicon-gate field effect transistors in which the gate electrode is made of silicon rather than of metal as in the prior art (R. 52-60; PX 17 H-l — H-3, I).

A field-effect transistor is a three-electrode electrical amplifier formed in a small body of monocrystalline silicon. Two electrodes, one designated as the “source” and the other as the “drain” are made by impregnating selected regions of the silicon body with impurity elements by a method known as “doping.” The third electrode or the “gate” overlies the transistor body between the source and the drain, the gate, however, being insulated from the transistor body. Appropriate voltage is applied to the gate enabling current to flow from the source to the drain, and variations of the gate voltage produce corresponding variations in the current flowing from the source to the drain (R. 21-29, 48-50; PX17A, B).

*1169 Field-effect transistors made according to the prior art processes employed a gate electrode made of a thin layer of aluminum, insulated from the underlying silicon surface by an ultra-thin layer of silicon dioxide. The placement of the aluminum gate electrode in proper alignment with the source and drain was critical and difficult since the dimensions involved were very small and the permissible margin of error was minute (R. 49-54). In the process which is the subject matter of the patent in suit, the transistor silicon body is coated with a thin insulating layer of oxide, a gate electrode of a thin layer of polycrystalline silicon is then deposited on the oxide, the oxide layer is then etched away in the regions where the source and drain are to be formed, and the portions of the transistor body thus exposed are “doped” by diffusion at a temperature of approximately 1000° C. During the diffusion step the silicon gate electrode acts as a “mask” insuring that the source and drain electrodes are located precisely adjacent to the outer extremities of the gate electrode. This efficient method of alignment could not be employed with an aluminum gate electrode since it would melt and flow at the high temperature required for diffusion (R. 52-60; PX17H-1 — H-3,1).

The present phase of the litigation is governed by 35 U.S.C. § 102(g), which provides in part:

In determining priority of invention there shall be considered not only the respective dates of conception and reduction to practice of the invention, but also the reasonable diligence of one who was first to conceive and last to reduce to practice, from a time prior to conception by the other.

The Court will, therefore, first determine the respective dates of conception and reduction to practice by plaintiff and defendant. 2

PLAINTIFF’S CONCEPTION AND REDUCTION TO PRACTICE

The record is clear that Hans Dill, plaintiff’s assignor, conceived of the silicon-gate invention in early May, 1966. Dill’s discovery was contemporaneously recorded, beginning on May 1, in impressive detail, and his notebook entries were witnessed by his laboratory colleagues (PX 3, pp. 209-211, 215-216; R. 67-80). Plaintiff contends that Dill reduced his invention to practice in tests on May 12, 1966, or alternatively, in tests on October 18, 1966. Defendant contends, however, that Dill’s invention was not reduced to practice before plaintiff’s patent application was filed on October 26, 1966.

Dill testified that shortly after he conceived of the silicon-gate device, he asked two colleagues, Rowland and Knoll, to prepare actual transistors by the new method (R. 80-84). Dill testified that the first field-effect transistors made with his silicon-gate process were completed by May 12, 1966 and were tested by him on that day. This testimony is corroborated by photographs of the masks used to prepare these experimental devices (PX 3A, 3B; R. 83-89), and by Dill’s contemporaneous notebook entry of the test results (PX 3, p. 215). However, plaintiff did not introduce into evidence any photographs of the actual silicon-gate devices, any reproductions of curves or test results for the devices, or any indication that witnesses other than Dill observed the tests.

Dill tested the experimental devices for transconductance — the amount of change in drain current resulting from a given change in gate voltage. The parties apparently agree that this test adequately measures the effectiveness of the device as a transistor (R. 169-170). Dill recorded the results of the May 12 tests as “etches perfect but no transconductance (10-50 microamperes per volt)” (PX 3, p. 215). He explained *1170 that when he first measured the devices, the transconductance was much smaller than he had anticipated, and he recorded “no transconductance.” Upon more refined measurement, however, the device tested 10 to 50 microamperes per volt, which Dill testified was about one-tenth the transconductance of a conventional field effect transistor at the time (R. 91-92, 170-172). Dill admitted on cross-examination that at the time of making the tests, he felt that the measured values amounted to no transconductance for all practical purposes (R. 171). Immediately following the May 12 tests, Dill sought out the help of other colleagues in improving the performance of his device (R. 172-175). There followed a series of diligent attempts, extending over a period of several months, to construct a successful silicon-gate transistor.

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374 F. Supp. 1166, Counsel Stack Legal Research, https://law.counselstack.com/opinion/hughes-aircraft-company-v-general-instrument-corp-ded-1974.