# This code is part of KQCircuits
# Copyright (C) 2022 IQM Finland Oy
#
# This program is free software: you can redistribute it and/or modify it under the terms of the GNU General Public
# License as published by the Free Software Foundation, either version 3 of the License, or (at your option) any later
# version.
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from math import sqrt
from kqcircuits.pya_resolver import pya
from kqcircuits.util.parameters import Param, pdt
from kqcircuits.junctions.squid import Squid
from kqcircuits.util.symmetric_polygons import polygon_with_vsym
[docs]
class Manhattan(Squid):
"""The PCell declaration for a Manhattan style SQUID.
This SQUID has two distinct sub-types automatically selected by loop-area.
"""
finger_overshoot = Param(pdt.TypeDouble, "Length of fingers after the junction.", 1.0, unit="μm")
include_base_metal_gap = Param(pdt.TypeBoolean, "Include base metal gap layer", True)
shadow_margin = Param(pdt.TypeDouble, "Shadow layer margin near the the pads", 1.0, unit="μm")
compact_geometry = Param(pdt.TypeBoolean, "Compact geometry for metal addition.", False)
separate_junctions = Param(pdt.TypeBoolean, "Junctions to separate layer", True)
offset_compensation = Param(pdt.TypeDouble, "Junction lead offset from junction width", 0, unit="μm")
mirror_offset = Param(pdt.TypeBoolean, "Move the junction lead offset to the other lead", False)
finger_overlap = Param(pdt.TypeDouble, "Length of fingers inside the pads", 0.2, unit="μm")
single_junction = Param(pdt.TypeBoolean, "Disable the second junction", False)
[docs]
def build(self):
self.produce_manhattan_squid(top_pad_layer="SIS_junction")
[docs]
def produce_manhattan_squid(self, top_pad_layer):
# geometry constants
big_loop_height = 10
loop_bottom_y = 1.5
self.metal_gap_top_y = 20 if self.compact_geometry else 26.5
self.width = 36 if self.compact_geometry else 38 # total width of junction layer
self.height = 17 if self.compact_geometry else 20.2 # total height of junction layer
bp_height = 5 # bottom pad height
tp_width = 10 # top pad width
small_loop_height = 5.2
h_pad_height = 1
v_pad_width = 2
pad_overlap = 1
# corner rounding parameters
rounding_params = {"rinner": 0.5, "router": 0.5, "n": 64}
# In order inner corner rounding radius, outer corner rounding radius, number of point per rounded corner
# convenience variables
delta_j = self.loop_area / (big_loop_height) # junction distance, a.k.a. loop width
tp_height = self.height - loop_bottom_y - big_loop_height # top pad height
bp_gap_x = -self.width / 2 + (self.width - delta_j) / 2 # bottom gap left edge x-coordinate
bp_gap_x_min = -self.width / 2 + 7 # fixed at minimum size
finger_margin = 1 # make hats brim this much wider for good finger connection
# adjust for small loop geometry
small_loop = tp_width > -bp_gap_x * 2
if small_loop:
bp_gap_x = bp_gap_x_min
delta_j = self.loop_area / small_loop_height
edge_height = 2.7
junction_shapes_top = []
junction_shapes_bottom = []
shadow_shapes = []
# create rounded bottom part and top parts
self.produce_contact_pads(
bp_height,
bp_gap_x,
tp_height,
big_loop_height,
junction_shapes_bottom,
rounding_params,
shadow_shapes,
)
# create rectangular junction-support structures and junctions
if small_loop:
self._make_junctions(
self.produce_tp_small(
edge_height,
small_loop_height,
loop_bottom_y,
delta_j,
finger_margin,
junction_shapes_top,
top_pad_layer,
junction_shapes_bottom,
shadow_shapes,
h_pad_height,
v_pad_width,
pad_overlap,
tp_width,
tp_height,
rounding_params,
)[3],
loop_bottom_y,
)
else:
self._make_junctions(
self.produce_tp_large(
delta_j,
finger_margin,
tp_height,
junction_shapes_top,
top_pad_layer,
junction_shapes_bottom,
shadow_shapes,
tp_width,
rounding_params,
h_pad_height,
)[1],
bp_height,
finger_margin,
)
self._add_shapes(junction_shapes_bottom, "SIS_junction")
self._add_shapes(junction_shapes_top, top_pad_layer)
self._add_shapes(shadow_shapes, "SIS_shadow")
self._produce_ground_metal_shapes()
self._produce_ground_grid_avoidance()
self._add_refpoints()
# Create top junction pad for smaller area
[docs]
def produce_tp_small(
self,
edge_height,
small_loop_height,
loop_bottom_y,
delta_j,
finger_margin,
junction_shapes_top,
top_pad_layer,
junction_shapes_bottom,
shadow_shapes,
h_pad_height,
v_pad_width,
pad_overlap,
tp_width,
tp_height,
rounding_params,
):
small_hat = [
pya.DPoint(-v_pad_width / 2, self.height - edge_height + pad_overlap),
pya.DPoint(-v_pad_width / 2, small_loop_height + loop_bottom_y + h_pad_height),
pya.DPoint(-delta_j / 2 - finger_margin, small_loop_height + loop_bottom_y + h_pad_height),
pya.DPoint(-delta_j / 2 - finger_margin, small_loop_height + loop_bottom_y),
]
junction_shapes_top.append(polygon_with_vsym(small_hat).to_itype(self.layout.dbu))
if top_pad_layer != "SIS_junction":
junction_shapes_bottom.append(polygon_with_vsym(small_hat).to_itype(self.layout.dbu))
small_hat_shadow = [
small_hat[0] + pya.DPoint(-self.shadow_margin, self.shadow_margin),
small_hat[1] + pya.DPoint(-self.shadow_margin, self.shadow_margin),
small_hat[2] + pya.DPoint(-self.shadow_margin, self.shadow_margin),
small_hat[3] + pya.DPoint(-self.shadow_margin, -self.shadow_margin),
]
shadow_shapes.append(polygon_with_vsym(small_hat_shadow).to_itype(self.layout.dbu))
small_hat[3].x += finger_margin
# create rounded top part
tp_pts_left = [
pya.DPoint(-tp_width / 2, self.height),
pya.DPoint(-tp_width / 2, self.height - tp_height),
]
tp_shape = polygon_with_vsym(tp_pts_left)
self._round_corners_and_append(tp_shape, junction_shapes_top, rounding_params)
# add top pad to bottom shapes in case another layer is used for the upper part of the squid
if top_pad_layer != "SIS_junction":
self._round_corners_and_append(tp_shape, junction_shapes_bottom, rounding_params)
tp_shadow_pts_left = [
tp_pts_left[0] + pya.DPoint(-self.shadow_margin, self.shadow_margin),
tp_pts_left[1] + pya.DPoint(-self.shadow_margin, -self.shadow_margin),
]
tp_shadow_shape = polygon_with_vsym(tp_shadow_pts_left)
self._round_corners_and_append(tp_shadow_shape, shadow_shapes, rounding_params)
return small_hat
# Create top junction pad for larger area
[docs]
def produce_tp_large(
self,
delta_j,
finger_margin,
tp_height,
junction_shapes_top,
top_pad_layer,
junction_shapes_bottom,
shadow_shapes,
tp_width,
rounding_params,
h_pad_height,
):
tp_brim_left = [
pya.DPoint(-delta_j / 2 - finger_margin, self.height - tp_height + h_pad_height),
pya.DPoint(-delta_j / 2 - finger_margin, self.height - tp_height),
]
junction_shapes_top.append(polygon_with_vsym(tp_brim_left).to_itype(self.layout.dbu))
if top_pad_layer != "SIS_junction":
junction_shapes_bottom.append(polygon_with_vsym(tp_brim_left).to_itype(self.layout.dbu))
tp_brim_shadow_pts = [
tp_brim_left[0] + pya.DPoint(-self.shadow_margin, self.shadow_margin),
tp_brim_left[1] + pya.DPoint(-self.shadow_margin, -self.shadow_margin),
]
shadow_shapes.append(polygon_with_vsym(tp_brim_shadow_pts).to_itype(self.layout.dbu))
tp_brim_left[1].x += finger_margin
# create rounded top part
tp_pts_left = [
pya.DPoint(-tp_width / 2, self.height),
pya.DPoint(-tp_width / 2, self.height - tp_height),
]
tp_shape = polygon_with_vsym(tp_pts_left)
self._round_corners_and_append(tp_shape, junction_shapes_top, rounding_params)
# add top pad to bottom shapes in case another layer is used for the upper part of the squid
if top_pad_layer != "SIS_junction":
self._round_corners_and_append(tp_shape, junction_shapes_bottom, rounding_params)
tp_shadow_pts_left = [
tp_pts_left[0] + pya.DPoint(-self.shadow_margin, self.shadow_margin),
tp_pts_left[1] + pya.DPoint(-self.shadow_margin, -self.shadow_margin),
]
tp_shadow_shape = polygon_with_vsym(tp_shadow_pts_left)
self._round_corners_and_append(tp_shadow_shape, shadow_shapes, rounding_params)
return tp_brim_left
# Create bottom junction pad
def _make_junctions(
self,
top_corner,
b_corner_y,
finger_margin=0,
):
"""Create junction fingers and add them to some SIS layer.
Choose 'SIS_junction' layer by default but 'SIS_junction_2' if ``separate_junctions`` is True.
"""
jx = top_corner.x - (top_corner.y - b_corner_y) / 2
jy = (top_corner.y + b_corner_y) / 2
ddb = self.junction_width * sqrt(0.5)
ddt = self.junction_width * sqrt(0.5)
if self.mirror_offset:
ddt += self.offset_compensation * sqrt(0.5)
else:
ddb += self.offset_compensation * sqrt(0.5)
fo = self.finger_overshoot * sqrt(0.5)
pl = self.finger_overlap * sqrt(0.5) # plus length to connect despite of rounding
def finger_points(size):
return [
pya.DPoint(top_corner.x + pl, top_corner.y + size + pl),
pya.DPoint(top_corner.x + size + pl, top_corner.y + pl),
pya.DPoint(jx - fo, jy - fo - size),
pya.DPoint(jx - fo - size, jy - fo),
]
finger_bottom = pya.DTrans(-jx, -jy) * pya.DPolygon(finger_points(ddb))
finger_top = pya.DTrans(-jx, -jy) * pya.DPolygon(finger_points(ddt))
squa = sqrt(2) / 2
if self.single_junction:
junction_shapes = [
(pya.DTrans(jx - finger_margin, jy) * finger_top).to_itype(self.layout.dbu),
(pya.DTrans(3, False, jx - finger_margin, jy) * finger_bottom).to_itype(self.layout.dbu),
]
# place refpoints at the middle of the junction. In this case, "l" and "r" coincide.
self.refpoints["l"] = pya.DPoint(
jx - fo - finger_margin + self.finger_overshoot * squa, jy - fo + self.finger_overshoot * squa
)
self.refpoints["r"] = self.refpoints["l"]
else:
junction_shapes = [
(pya.DTrans(jx - finger_margin, jy) * finger_top).to_itype(self.layout.dbu),
(pya.DTrans(0, False, jx - 2 * top_corner.x, jy) * finger_top).to_itype(self.layout.dbu),
(pya.DTrans(3, False, jx - finger_margin, jy) * finger_bottom).to_itype(self.layout.dbu),
(pya.DTrans(3, False, jx - 2 * top_corner.x, jy) * finger_bottom).to_itype(self.layout.dbu),
]
# place refpoints at the middle of the left and right junctions
self.refpoints["l"] = pya.DPoint(
jx - fo - finger_margin + self.finger_overshoot * squa, jy - fo + self.finger_overshoot * squa
)
self.refpoints["r"] = pya.DPoint(
jx - fo - 2 * top_corner.x + self.finger_overshoot * squa, jy - fo + self.finger_overshoot * squa
)
junction_region = pya.Region(junction_shapes).merged()
layer_name = "SIS_junction_2" if self.separate_junctions else "SIS_junction"
self.cell.shapes(self.get_layer(layer_name)).insert(junction_region)
def _add_shapes(self, shapes, layer):
"""Merge shapes into a region and add it to layer."""
region = pya.Region(shapes).merged()
self.cell.shapes(self.get_layer(layer)).insert(region)
def _add_refpoints(self):
"""Adds the "origin_squid" refpoint and port "common"."""
self.refpoints["origin_squid"] = pya.DPoint(0, 0)
self.refpoints["center_squid"] = pya.DPoint(0, 4.1 if self.loop_area < 100 else 6.5)
self.add_port("common", pya.DPoint(0, self.metal_gap_top_y))
def _produce_ground_metal_shapes(self):
"""Produces hardcoded shapes in metal gap and metal addition layers."""
# metal additions bottom
x0 = -12 if self.compact_geometry else -13
y0 = -1
bottom_pts = [
pya.DPoint(x0 - 3, y0 - 1),
pya.DPoint(x0 - 3, y0 + 2),
pya.DPoint(x0 - 5, y0 + 2),
pya.DPoint(x0 - 5, y0 + 5),
pya.DPoint(x0, y0 + 5),
pya.DPoint(x0, y0 + 1),
]
shape = polygon_with_vsym(bottom_pts)
self.cell.shapes(self.get_layer("base_metal_addition")).insert(shape)
# metal additions top
y0 = 12 if self.compact_geometry else 14.5
top_pts = [
pya.DPoint(-2, y0 + 3),
pya.DPoint(-2, y0 + 1),
pya.DPoint(-1, y0 + 1),
pya.DPoint(-1, y0),
pya.DPoint(-4, y0),
pya.DPoint(-4, self.metal_gap_top_y),
]
shape = polygon_with_vsym(top_pts)
self.cell.shapes(self.get_layer("base_metal_addition")).insert(shape)
# metal gap
if self.include_base_metal_gap:
pts = bottom_pts[::-1] + [pya.DPoint(-20.5, -2), pya.DPoint(-20.5, self.metal_gap_top_y)] + top_pts[::-1]
shape = polygon_with_vsym(pts)
self.cell.shapes(self.get_layer("base_metal_gap_wo_grid")).insert(shape)
def _produce_ground_grid_avoidance(self):
"""Add ground grid avoidance."""
w = self.cell.dbbox().width()
h = self.cell.dbbox().height()
protection = pya.DBox(-w / 2 - self.margin, -2 - self.margin, w / 2 + self.margin, h - 2 + self.margin)
self.add_protection(protection)
def _round_corners_and_append(
self,
polygon,
polygon_list,
rounding_params,
):
"""Rounds the corners of the polygon, converts it to integer coordinates, and adds it to the polygon list."""
polygon = polygon.round_corners(rounding_params["rinner"], rounding_params["router"], rounding_params["n"])
polygon_list.append(polygon.to_itype(self.layout.dbu))