# US 5,352,627 A · Monolithic high voltage nonlinear transmission line fabrication process > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,352,627 A - Document ID: US5352627A - Status: Granted - Kind: A - Application number: 08/058,369 - Filed: 1993-05-10 - Granted: 1994-10-04 - Earliest claimed: 1993-05-10 - Inventors: Gregory A. Cooper - Web page: https://patentgrep.com/patent/US5352627A ## CPC - H10D 8/043: {of planar diodes} - H10D 84/05: using Group III-V technology - H10W 10/00: Isolation regions in semiconductor bodies between components of integrated devices - H10W 10/01: {Manufacture or treatment} - H10D 62/85: being Group III-V materials, e.g. GaAs - H10D: INORGANIC ELECTRIC SEMICONDUCTOR DEVICES - H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10 ## Abstract A process for fabricating sequential inductors and varactor diodes of a monolithic, high voltage, nonlinear, transmission line in GaAs is disclosed. An epitaxially grown laminate is produced by applying a low doped active n-type GaAs layer to an n-plus type GaAs substrate. A heavily doped p-type GaAs layer is applied to the active n-type layer and a heavily doped n-type GaAs layer is applied to the p-type layer. Ohmic contacts are applied to the heavily doped n-type layer where diodes are desired. Multiple layers are then either etched away or Oxygen ion implanted to isolate individual varactor diodes. An insulator is applied between the diodes and a conductive/inductive layer is thereafter applied on top of the insulator layer to complete the process. ## Claims ### Claim 1 A process for fabricating a monolithic, high voltage, nonlinear transmission line, comprising the steps of: a. epitaxially growing a low doped, active, n-type layer on a heavily doped, n-plus-type substrate; b. epitaxially growing a heavily doped, p-type layer on said low doped, active, n-type layer; c. epitaxially growing a heavily doped, n-type layer on said heavily doped, p-type layer; d. making ohmic contacts on said heavily doped, n-type layer, thereby forming a laminated varactor diode; e. deactivating a designated volume of portions of each said heavily doped n-type and p-type layers and said low doped, active, n-type layer in a manner to leave independent and electrically isolated islands of laminated varactor diodes with a remaining portion of said low doped, active, n-type layer in common; f. depositing a nonactive and nonconductive layer within and upon said designated volume enclosing said deactivated n- and p-type layers, exclusive of the volumes above said ohmic contacts; and g. depositing a conductive layer on said nonconductive layer including and filling said volumes above said ohmic contacts. ### Claim 2 (depends on 1) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 1, wherein said heavily doped, n-plus type substrate of step (a) is Gallium Arsenide (GaAs). ### Claim 3 (depends on 2) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 2, wherein said dopant in said n-plus type substrate is Silicon (Si). ### Claim 4 (depends on 3) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 3, wherein said substrate dopant is approximately 2.times.10.sup.18 /cm.sup.3. ### Claim 5 (depends on 1) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 1, wherein said low doped, active, n-type layer of step (a) is GaAs. ### Claim 6 (depends on 5) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 5, wherein said active n-type dopant is Si. ### Claim 7 (depends on 6) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 6, wherein said active n-type dopant is approximately 6.4.times.10.sup.15 /cm.sup.3. ### Claim 8 (depends on 7) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 7, wherein said low doped, n-type layer is approximately 5 microns thick. ### Claim 9 (depends on 8) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 8, wherein said n-type dopant is non homogeneously distributed throughout said low doped, n-type layer. ### Claim 10 (depends on 1) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 1, wherein said heavily doped, p-type layer of step (b) is GaAs. ### Claim 11 (depends on 10) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 10, wherein said p-type dopant is Beryllium (Be). ### Claim 12 (depends on 11) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 11, wherein said p-type dopant is approximately 1.times.10.sup.18 /cm.sup.3. ### Claim 13 (depends on 12) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 12, wherein said heavily doped, p-type layer is approximately 0.2 microns thick. ### Claim 14 (depends on 1) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 1, wherein said heavily doped, n-type layer of step (c) is GaAs. ### Claim 15 (depends on 14) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 14, wherein said n-type dopant is Si. ### Claim 16 (depends on 15) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 15, wherein said n-type dopant is approximately 1.times.10.sup.18 /cm.sup.3. ### Claim 17 (depends on 16) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 16, wherein said heavily doped n-type layer is approximately 0.5 microns thick. ### Claim 18 (depends on 1) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 1, wherein said ohmic contacts of step (d) are formed by metal deposition on said heavily doped, n-type layer. ### Claim 19 (depends on 1) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 1, wherein said deactivating process of step (e) consists of etching away of said designated volume. ### Claim 20 (depends on 1) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 1, wherein said deactivating process of step (e) consists of implantation of Oxygen ions in said designated volume. ### Claim 21 (depends on 1) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 1, wherein said nonconductive layer of step (f) is a polyimide. ### Claim 22 (depends on 19) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 19, wherein said nonconductive layer is approximately 20 microns thick. ### Claim 23 (depends on 1) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 1, wherein said conductive layer of step (g) is Gold (Au). ### Claim 24 (depends on 21) A process for fabricating a monolithic, high voltage, nonlinear transmission line according to claim 21, wherein said conductive layer is approximately 10 microns thick.